First of all, I do feel that this generation has been less than stellar compared to previous generations. But as for your reasoning, meaning the reasoning of the OP, I don't think its quite sound. And I can explain why.
Are rabid fanboys horrible? Yes. But are they ruining the games themselves? No. If anything, game designers are ignoring making certain games and genres because of 'rabid fanboys'. And other games or genres which have 'rabid fanboys' have seen a decline in quality. And is FPS really hurting this gen? No. If anything, its helping many companies make lots of money. I'm not even going to touch cosplay as a serious topic.
Other things such as the HD obsession and the console failure rate are also a negative impact, but they're also not as major as the real issue. Which the real issue is the lack of as many quality games being made. And this is due to the designers themselves not focusing on both the fans wants and all the available markets.
When it comes to the XBOX360 and PS3, developers are mostly either developing games which will a) look the best or b) cater to the biggest niche market and cost the least to develop. And if you think something like MGS or GTAIV or Mass Effect 2 cost millions upon millions and was the pinnacle of game development, realize that companies like Sony and MS were subsidizing the development of those games.
Now also realize that this gen has been suffering because these same developers have been grossly ignoring the dominant console, the Wii. You can give all the excuses you want, but when it comes down to it, the Wii has the biggest slice of the pie and no real third party developer has put forth any effort on the system beyond what you could call a 'B' title (aside from possibly Monster Hunter Tri). This is the real prime example of why this generation is failing. Because companies are putting all their eggs onto two systems that are lagging far behind the more popular system, and coming up with whatever excuse they can to say the Wii 'can't make money'.
Six upcoming games you should look into:
