That's just the way android devices are. If you want constant updates, get a Google phone. There are way too many devices out now for any company to keep up with updates. Simply the reason why there are newer, better phones that come out every couple months. You want Android and its hardware to slow down for updates? If you're waiting on at&t/manufacturers to release everything you're going to wait for a long ass time. You're on the wrong platform if you don't even know what the great devs at XDA offer all of us. They are our Robin Hoods giving our poor phones the food and energy to be better.
Also, if it's not an iPhone, lots of your friends (if non techy or apple fanboys) won't have one of ours. I left iPhone because both my parents own one (to my encouragement) and couldn't feel like a power user anymore haha.
Accessories, i'm sure there are if they sell the phone as well (AT&T, Best buy, Frys, Costco?) If you're talking about more choices? You're on the wrong platform as well. Only Apple and it's universal 30pin port for all mobile devices make it easy for manufacturers to make so many. With androids different manufacturers and port locations there is nothing universal about it. So they make a few per device.
This is why tech industry and bloggers continue to call it fragmented. But what it does do is give you choices. Something Apple can't give us. One choice a year in a closed ecosystem? Forget it.
As for the Infuse, compared to GS2. To me it's like when I had the 3GS and the 4 came out. Sure I was jealous of the new sexy, but what I had in my hand was still VERY capable of doing what I needed to do. Speed was still there, still smooth. Same with the Infuse, you will not see much difference. GS2 is incremental in hardware. What's a split second, opening up an app? You will see difference in heavy 3d gaming and better flash experience of course but is that all to a device that will mainly text,email, phone? Though you won't see me persuading an upgrader to choose a Infuse over the GS2. You crazy? Get the GS2! For us Infuse owners though, if you're don't mind paying the full price for GS2, go ahead but I would wait out on something more, like an LTE phone or quad-core that's coming next year? Why not give our device a chance.
This is coming from someone, though, with a custom rom installed. If you're not on one, it's not being used to it's full potential (I say to this with whatever official at&t update ever released or will release) and you maybe won't see what I see in the experience of this phone.