When you are struggling year by year with sales and recognition, your only way out is to standout from the crowd, no matter how good your marketing is if you have a mediocre product you can fool some but not everybody, so in the situation that HTC is right now, they MUST do both, good marketing and a standout phone, and right now they don't have any of those.
I have my S7 edge since launch and bought the HTC 10 from T-Mobile the same day it was available at my local store and for the past month and a half I've been switching phones every 5-7 days, my preference, the S7 edge, too many things that I use, too many standout features, things like Edge screens (some hates them and others say that are gimmicks, but nobody can say that they are unique), IP68 (No worries living on an Island on the Caribbean because of Dirt and water), Wireless Charging and fast Wireless Charging (Simply great and convenient), Bigger Battery, Better Screen (personal preference of course), better camera ( even with latest HTC 10 updates it still a little behind the Samsung ones, I can tell you by doing a direct comparison with the 10 and my wife's S7 at my daughter's Graduation) , Samsung Pay (Unique and great feature), MultiView (Multi-Tasking), Native Video calling and Enhanced Messaging, etc...
I'll stop right there because it's obvious that you should have my point already, when you are in HTC position you need to come with a Killer phone, killer in every aspect, that even AT&T will beg you to allow them to sell it, HTC has created in the 10 their best phone yet, but besides the Sound (only by headset because the speakers to me are just meh) they just have "another" great android phone, nothing to standout, and that's exactly their problems right now, how can they attract people to buy their phones if they are not even on the stores display, people on forums are just an insignificant percent of the total market, people that know about the HTC 10 are people like us that come to forums like this and demands the phone from the stores (like I needed to do because the employees didn't even know it had been released) and then to pay the exact same price than a S7? Ehh for most people that's an immediate no, most people don't even know who HTC is, and for us that know, we have serious doubts of how long they can keep the business rolling, so no matter if you offer me 10 years of free Screen and battery replacement, what matters to me if you are going to be there to back it up.
It's simply a shame as the HTC 10 is a great phone, I certainly enjoy using it, but don't fool yourself the S7 edge is Samsung's best yet also and those who say that it lags and that 10 bests it in other than the Sound either they have never used a S7/S7 edge, got a bad one or are simply fooling themselves. Both are great phone and obviously Samsung will always sell ( at least for now) tons more than HTC and the rest of OEMs on the Android world, but it's not people's fault or ignorance the reason of HTC debacle, it has always been their stubbornness on adjusting to the market and its changes, great phone but not a standout one.