As stated the chances of this actually happening are very small, worse case will likely be MS pays them off or Next Gen will be starting a little sooner. This will ONLY effect new console sales, not sold consoles or there online business.
If things do go badly, the next gen might not save anything. If it relies on the same patents that were violated in the 360, those would also be blocked or it'd be delayed until they could be removed.
But, since Obama does have the final say, I seriously doubt he'd ban it.