No, a lot of retail games are already available via XBLA/PSN, for example Battlefield 3 was Day and Date. I think EA's been exceptionally active on this front.
Yeah I know, Games on Demand, but that's only optional. All big budget games will continue to be released on retail as well. But in the future they could use something like Steamworks for console games as well, which means you gonna have to think twice before forking out 60 EUR for something that may turn out stinker.
But this is only a natural development, as this means many companies are gonna go out of business as people are starting to get more picky, so only a few best survive for blockbuster productions. The market always regulates itself.
Not sure what this means for Obsidian though.