While I think 5 years is way to early of an estimate, some people in here are kind of missing his point. This isn't really about the games at all, it's simply an economic prediction. The path that Sony and Microsoft are taking their consoles on heads towards an area that Microsoft windows already dominates. As consoles get more PC-esque they will have to eventually deal with the juggernaut that is Microsoft Windows, a product that outsold all the past gen consoles combined. It's pretty simple to understand once you take a look at what Sony wants to do.
The PS3 Linux is one of Sony's first steps in a maneuver to try and dethrone Microsoft. Why Microsoft? Because Sony wants to own the standard platform through which all media passes, and so far Microsoft Windows is far closer to become that platform. Whys that such a good thing? It's because by virtue of how a purely information product scales to the mass market, Microsoft generates HUGE revenue for approximately zero effort. It's the position that every company wants to be in, and Sony thinks they have a shot at taking it away from Microsoft. Sony's starting by trying to control the optical disk standard (Blu-ray), and by turning the PS3 into a proprietary PC via PS3 Linux. Eventually, they want you doing everything on the PS4 or PS5 that you now do with Microsoft Windows, and that's why I think they will fail.
The market is resistant to change, and when Sony makes their move, Joe Sixpack isn't going to be using PSWrite, he'll be complaining about the lack of MSWord. He won't be using PSExplore, he'll be looking for the Internet Explorer icon. And he'll buy Microsoft's "console" that runs Microsoft Windows because it has all the applications that he is used to using. In addition to that though Microsoft saw the Sony console -> PC transition as being one of the times that Windows could be dethroned. So they are preemptively defending themselves, and as much as the Xbox supporters don't like it, the Xbox only exists to protect Windows. In the future, when Sony tries to push the console market to replace Windows, Microsoft will have set themselves up to be where the "console" users will transition to, and you can be damn sure Windows will be there to great them with open arms.