More potential sales for one since ps4 sold more units than xb1
On NeoGAF where sales are argued over exhaustively, it's easy to think that games developers care as much about sales as we'd like to think. But they really don't. Publishers do, sure, but so long as developers get to make the game they want to make, which is successful enough to let them make another game after that, they're ecstatic, trust me. Kojima will have this luxury wherever he goes.
MS is more likely to have Kojima?
Again, I didn't say that. And I'm not seeing much evidence regarding your points. What I am seeing is VIPs fleeing 2nd party studios, TLG being stuck in development hell for half a decade, a ton of debt hanging over Sony, property being sold off, studios closed, Vita being abruptly retired, and Yu Suzuki being paraded on stage like an orphan begging for tablescraps. Basically, a lot of cost-cutting and conservatism. Point me in the direction of evidence to the contrary, or an example of Sony's gaming arm spending cash akin to MS' Minecraft purchase, and I'll happily embrace it.
My observation is merely that
if Kojima is looking to work on projects with 40m+ budgets like he's used to, and
if MS think he's worth it, they'll be able to make Kojima a very competitive offer that with all manner of financial and developmental perks, which Sony in all likeliness probably can't.