Diablo 3 is a day 1 purchase for me. Don't care one whit about the requirements for a persistent connection. I've had more than enough experience with MMOs to know that games requiring an internet connection generally work just fine.
Rage...bit of a different horse. Just don't know enough about the game other than it kind of looks like a more serious and realistic Borderlands...maybe. If I were to buy it, wouldn't care about requiring a persistent connection to play.
I agree that this is the direction the industry is heading. You'll be seeing more games being released for free with content bundled up into neat little packages that can be sold for a few bucks...all tied to an online server/authentication. It's the best business model now adays. No mucking about with distribution, no worrying about used game sales, piracy...if a game is successful it's already set up to continue dumping more content in, which is much cheaper than developing a new game from scratch.
Like it or not, piracy has lead to this. Right or wrong, publishers believe that piracy is a threat to the traditional business model and having an online game greatly reduces that. If nothing else, it will strip one excuse for failure away from publishers and developers. "Our game would have done well if it weren't pirated so much!"
This is the future. Anyone not wearing blinders saw this coming a decade ago. Adapt, or get a new hobby. Cause no amount or raging in the comments of gaming news sites will change the minds of the suits ponying up the money to make our digital crack.