Sounds a lot like my conclusion a while ago which is high development costs and long development times which yes is the reason why some developers are struggling in such prosperity.
What it does is takes middle sized and small devs out of the picture. They just can't compete. So the independent developers like Free Radical and Factor 5 who can only make one game at a time go down if it flops like we've seen.
360 and PS3 are really only viable markets for the large developers like Activision, EA, THQ, Ubisoft, Capcom, Namco, Sega, and Take Two. These are the devs that can put out 30-40 titles a year and have a few of them be big hits and be fine. But everyone else has to hope their game is the next big thing which is why they spend so much money on marketing to hype up the title.
Thus in such prosperity we are seeing more devs go down because of this which is lessening the diversity in the market. This is why people have been saying one console/one developer future because this is what would happen if everyone did this.
Luckily such things as handhelds, Wii, PS2, XBLA/PSN/WW and PC still exist that allow for cheaper but influential development that doesn't always drain the pocketbook. Thx to this we have been able to keep a lot of the smaller/medium sized developers alive. Also it allows more risk taking such that we get games like World of Goo, Braid, De Blob, Echochrome, ect. Also if the other devs start to learn that exclusive to one of the HD platforms isn't a good idea then they'll be able to stay alive longer. Have games like Too Human, Lair, and Haze on PS360/PC then they'll be fine.
