Why does Samsung need to "upgrade" their manufacturing processes? are you an expert at this? Is there evidence that their devices are less reliable than other companies? The use of plastic is a choice on their part but in no way means it is defective or in need of upgrade as you suggest.
If I were Samsung and I looked at the RUNAWAY success that the "cheap, plasticy, child's toy" Galaxy series has become I'd say the market has spoken and Samsung is giving consumers what they want.
Am I an expert? No. I'm not an expert as much as you're not an expert or anyone else in this thread is an expert. I've simply owned a Samsung device for ~ 1.5 years, and based on my own experience, the fit and finish of HTC devices is vastly superior--in my hand, in my use, and in my opinion--to Samsung.
What do I base that on? 4 different Galaxy Nexus devices since I took ownership. Each for a flaw in the manufacturing process, may it be red fibers under the screen, screen burn in, faulty buttons, a volume rocker that inexplicably stopped working, and an overly noisy and creaky chassis.
What else do I base that on? Each and every review of these two devices. No matter which device "wins out," one constant is how impressed everyone has been with the One, its design, and its finish.
Samsung is a for-profit company. They are much, much better at being a company than HTC has been. They sell phones easier than most of us can breathe. They do plenty right. But to fall back on "if it's not broke, don't fix it" defeats the very purpose of innovation.
Let's talk about innovation, shall we? Where does Samsung innovate? Features. S Voice. Hover. S Translate (sp?). The Camera. Camera Software. The evolution of AMOLED screens. Where do they not innovate? Well, depending on preference, screen technology, design, software, and build. Google launched the Galaxy Nexus without a physical home button. Remember, the Nexus device is a reference device. It's Google's sermon on what it believes Android should be and where Android should be directed. The Galaxy Nexus is without an external SD slot (however, there is an /sdcard folder). The Galaxy Nexus is without a home button. From ICS forward, Android shifted its priorities from over the top abundance and gaudiness to stripped down, pure, and simple. Look at Gingerbread. Look at ICS. Look at Jelly Bean. Notice the difference? GB was stripped away, beautified, and simplified, begetting ICS. ICS was improved internally and then with additional features, resulting in JB.
Now, look at the manufacturers. Sense 4.0 was a distinct and aggressive departure from prior versions of Sense. It, like most pieces of software, still had issues--primarily multi-tasking. But HTC decided to follow Google's lead and they started to simplify, beautify, and strip down Sense. This resulted in a very, very usable OS, but without the burdens of RAM/resource intensive features that waste device capability. The One X, porous finish aside, was an incredible device. Its screen was otherworldly, easily besting other screens by a very unscientific comparison.
(See also Motoblur, particularly the version in the newer RAZR HD models.)
What did Samsung do? Iterative hardware evolution. They increased the internal specs, giving the GS3 an enormous amount of horsepower. But it needed it. Have you ever compared TW and AOSP from a resource consumption perspective? TW taxes the device more than any other mainstream skin. The GS3 came with 2 gigs of RAM. At first, people were shocked--what the hell would you use it for? And then, once people dug into TW and used it, it became apparent: in order to future proof the GS3, it had to withstand Samsung piling stuff into TW. It can't do that without gobs of RAM.
What else did Samsung do? They created that blue finish, which while looking fairly awesome, it was marred by build quality issues in the first batch (remember the white blotches? I do, and surely the forums' archives do). They kept the home button. They kept the SD card slot. Samsung made a conscious choice to not follow Google. It resulted in a tremendous amount of sales, so from a business perspective, they succeeded. But remember, the GS3 was built on the surprise of the GS2. That device was the first Samsung device that captivated Android. Remember, again, HTC had that early lead. The Incredible was arguably the first widely popular device, with Verizon doing its best to tout the Incredible as an iPhone competitor (until it received the iPhone 4 in the fall of 2010).
HTC has "failed" because its business side was simply a mess. The Thunderbolt should have never been released. But, for its faults, it was daring. I believe it was Verizon's first 4G phone. Unfortunately, the tech did not support 4G LTE nearly as well as it does now. Batteries were chewed through in mere hours, the finish was easily marred, and I've yet to see one currently that has its kickstand intact. They then released somewhat lackluster EVO devices, further pushing their "market cache" down while Samsung had the GS2/Skyrocket/Epic. Before you blinked, by late 2011, HTC had fallen and Samsung placed itself in a position to become synonymous with Android to the casual user. This is the position we inhabit currently.
Samsung took further leads from Apple (aside from some mild to moderate patent infringement). They kept the same design language in its big devices--namely the Galaxy series. For someone like me with poor sight, it's hard to distinguish a Note 2 from a GS3 from afar. They're the same thing at a glance, except one is a tad bigger. Obviously, folks are buying this, and Samsung, as a business, has no reason to depart. But that does not mean it is the best, a term which is measured by variables neither you, I, or really anyone else can objectify. It means that they found what works and will maintain that "attack." Samsung has become complacent with its position--and why not, it's working. But complacency will ultimately breed devolution, because without a will to change and to adapt, or without risk in innovation, other technologies and products will surpass it. The first iPhone--and heck, iPhone 4--was arguably the best mobile device ever created at the time. Look how far we have come from that time! The iPhone spurred innovation, resulting in the Android we see today, Windows 8, even Blackberry 10. Do you know why Apple "loses" sales (if one could even call it that?)--because folks like myself and countless others want something different. Samsung no longer stands for different. It stands for success. It stands for complacency. It stands for safe. Buy a GS4 and you won't have to worry, for you already know the faults, defects, and positives of the device. That's great for business and great for casual users. But for those surfing on the fringe, as many hobbyists are, it becomes harder and harder to justify siding with a company so seemingly pleased with itself that it has stopped taking risks.
HTC took a big risk with the One. So far, the reviews from early adopters and the media are very positive. It will not beat Samsung. Heck, it might not even save HTC. But you know what it did? It took a shot for the moon. HTC decided that it was going to build a device with an eye towards perceptive hardware quality. That meant metal. You know how "wrong" that is? Well, look at all those Macbooks, like the one I'm typing on right now. They sell for a few reasons, including the fact they are gorgeous and crafted from metal. Some folks find inherent pleasure in touching a metal device. I love metal, personally--both musically and materially. What else did HTC do? It further improved the One X's gorgeous screen, increased it to 1080p HD, and demolished Apple's own retina standards. They stripped Sense further, added a few key features, and have bet the house on their device. Will it work? We'll find out in a year.
But what's shocking about this, personally, is the One doesn't remind me of an iPhone. You know what it reminds me of? The GS2. I only wish (and hope) that Samsung decides to go back to that type of work for future devices. In its current lineup, the Note II is easily the most impressive and innovative device. A phablet is a hard sell for a lot of users (I have small, Mediterranean hands), but the Note II took an OK product (sorry, Note fans) and drastically improved it. The Note III, for me, will be the true measure of where Samsung stands. Not as a business. But as an innovative technology enterprise. So from that perspective, I could only hope that they see the One and decide that "going for broke" can yield results and inspiration.
(Any and all spelling and grammatical errors remain my own.)