The biggest problem MS will have at the start of next gen is PS5 most likely having backwards compatibility. Unless Sony don’t screw this up, I doubt MS will have a chance of getting close worldwide. They might have a chance to lead in their home market, but it’ll be nowhere close to how it was in 360 times.
Console sells don't matter but software sells does. In fact, Phil Spencer said in a theoretical situation if they can sell fewer consoles, but more software will be ideal. If you buy a ps5 and buy 1 game a year or throw it in the closet it does Sony no good.