Let's talk about some old games. Take, for one, Halo 2. It's now going to be permanently offline, as a result of it being connected to Microsoft's services. Let's go back though. Take a look at Jedi Knight. Can you play that online anymore? Nope. Microsoft service. Dead. Any of those other MSN/"Zone" games? Dead. At least DirectPlay supported LAN in the same manner as online, so the games all still support that.
But - Quake 2? Still kicking. Released the same year as JK, too, IIRC. Microsoft continues to do this; they entice game developers with easy online/multiplayer libraries and then kill the service to force people to upgrade. I fear for all the Games for Windows games; that's why I'll never buy a title that uses Games for Windows Live. 10 years down the road, all those games will be permanently offline too, as will (likely) all this trash like CoD42 which uses an even smaller and even more restricted network. Meanwhile, I'll still be playing Quake 3 (and hopefully RAGE, now that it's not being published by EA).
DirectPlay. Live. When will developers learn?