Why switch and not ps4? Their games would be much easier to port over to and gamepass would be much more profitable on the ps4.
Well, if this rumor is true, you have to remember that MS is actually giving it another go next gen. Doing this on the PS4 would hurt their chances, since they compete much more with Sony than Nintendo, and that would 100% make an XB2 unnecessary. This wouldn't surprise if it were true, as they are really making a bunch of moves lately to make a transition from HW/SW to just SW easier. My guess is that if they do stumble out the gate, again (which is very possible if we get a very powerful PS5 @ $399 w/ B/C with PS4), they will just stick with PC + Nintendo develop, much like Sega did after the Dreamcast failed to change their situation in the HW market. And much like Sega, if the PS5 is on its way to 100M, too, the higher ups and investors will probably be insisting on releasing games on PS5, as that is where they will flourish the most with core console gamers.