I don't think most people will care that much about a new Pink Floyd record. Yeah, it will do well, but it's not going to burn up the charts like, say Adele would. I don't know when U2 is going to release their record, but I doubt Pink Floyd has much to do with it. If it ever comes to U2 having to move off a Pink Floyd release date, they might as well just hang it up.
Now, if and when Pink Floyd tours, that's another matter. Such a tour, like a Zeppelin reunion tour, would be a monster. But its the tours from these dinosaur acts people care about, not their mediocre "new" material.