GTA San Andreas was on the original Xbox in the GTA Collection. All the GTA games are also on PC
The original Tomb Raider was on both PSX and Saturn as well as PC. TR 2-4 were on PSX and PC. TR Chronicles and Revelations was on PSX, Dreamcast and PC. TR Legends was on PS2, PS3, Xbox 360 and PC, Anniversary and Underworld were on PS3, Xbox 360, and PC. I left out Angel of Darkness becase it sucks, but it wasn't an exclusive either. No Tomb Raider has ever been exclusive. A few have been console exclusives, but not since the 32bit days.
As for Tekken and Crash Bandicoot. I would say that fighters and platformers have been replaced by FPS and TPS. Fighters and platformers just aren't popular anymore. Frustrating for hardcore fans, but true. The same is true for JRPG. Now the majority prefers WRPGs like Mass Effect and Elder Scrolls. Final Fantasy didn't addapt and has lost ground to WRPGs. FF13 is so Japanese in style that it couldn't be more different from WRPGs if it tried. I think that has more to do with appeal to the current tastes of gamers than going multiplatform and pissing off fanboys.
I would also assert that MGR:R has so little to do with MGS that one can not assume that they appeal to the same demographics. DMC is also very different from Devil May Cry. It's so different that the fans of the original flat out refused to buy it. But it was already a style of gameplay that was falling out of style long before DMC came to light.
As for the whole "going multiplatform" topic, I think it's always a good idea. Reaching new players is always worth it. The era of the PS2 is over and publishers can't rely on it as their only platform. It now takes at least two consoles to reach the same amount of people. But tastes changes and fans don't always come back for more. It's rare for sequels of any kind to continue to grow in popularity forever. Eventually they peak and fall or at least slow.
