He went on to say that Live will be the primary entertainment center for Windows Phone handhelds. "If we have that and the PCs to leverage, that will be a big Live base," he added. "It's our job to make 'buy a movie in one place and play it everywhere, buy a game in one place and play it everywhere.' Making things portable will be a big focus of ours."
What I speculate from this is that you buy one game and can play it on your Xbox, PC, or phone, more or less "only on Xbox" titles become "only on Windows" titles. I also speculate that the XBL subscription doesn't just allow for multilayer action on MS hosted servers, but also allows you to purchase one game for three devices. When you purchase a Steam game you can only play that game on a PC, where as this service seems to be about being able to play on any Windows OS. Assuming that is what MS means with their above statements and assuming that the prices don't change, little math will go a long way.
New MS only Game of the year comes out:
Xbox $49.99
PC $49.99
WMP8 $19.99 (assumes that games on phones are limited)
XBL subscription $60/year
If you have the subscription you pay $49.99 and can play the game on any platform savings (assuming you own all three and want to play on all three) of $69.98 over purchasing each without the service. Even if you only wanted to play the games on the phone and your PC it would pay for itself if you bought 3 games a year. And that is what MS is really trying to do; they want to give you incentive to purchase all three of their platforms or at least a PC/XBox and a phone. One so they can sell more software and two so they gain a large and always profitable subscription base. And knowing MS the way I do any MS game where they host the servers you will have to pay the subscription even on the PC anyway when the new Xbox comes out.
I don't like console gaming but the thought of playing games for "free" on my phone when I purchase one on my PC sounds like a good deal, but I played WoW off and on for a few years so I'm past the "I won't play to pay" thing.