Your ridiculous exaggerated and sensationalist thread titles make me immediately biased against whatever you're reporting.
These 15 games are nothing titles.. MS has already been putting force behind getting games on Windows Phone 7, did that make it a big hit? Not in the slightest. This is not about XBLA, this is about PlayXBLA which is specifically games Microsoft contributed to. No reason to believe that this will extend to some huge tour de force of gaming.
It's not like MS can port other XBLA games themselves, they're going to need ports from the original developers. And if there's no big momentum behind the platforms already it's going to be a tough sell. Popularity in the indie scene? Not really, XBox Live Indie Channel is a disgrace and XBLA, while amenable to lower budget stuff, still has a reasonably high entry cost. Much higher than iOS and Android. For that reason the games also tend to sell for a decent amount more than phone and tablet games, which is going to make it hard for developers to want to migrate them to Windows phones and tablets.
