Games for Windows Live is the reason Gears of War and Halo 2 sold so badly on PC and Gears 2/Halo 3 never got a PC version when it mattered.
They tried fucking charging for it, the way they charge you for Xbox Live.
It went so badly they made it completely free in an attempt to recoup sales, and then kept trying with it for the entirety of 7th gen instead of letting it just die to Steam.