Both shows are being cancelled by G4 as part of an effort to repackage the ailing network as more "guy-centric". In other words, more episodes of COPs, Ninja Warrior, and whatever other reality shows they can get on the cheap.
While I never watched either show a lot, X-Play was a pretty good show. Attack of the Show, though, not so much. It was good in the beginning, but degenerated into internet clips, commercials for electronics (phones, computers, tablets, etc.) disguised as reviews, and low-brow comedy. A poor successor for The Screen Savers, the show that it replaced.
Of course, G4 ended up in its current situation because of their over reliance on reality shows. They had a slew of good shows after they merged with TechTV, but their execs instead chose to cut almost all the meat from the bone and fired the majority of their on-air personalities and cancel all but two of their shows. Well, looks like their stupidity has finally bitten them in the ass and they're fated to be a Spike clone.
Can't say I'm heartbroken.