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.
But we know thats not how the correlation is currently true though. The numbers of owned games is significantly higher this gen than last... now if you had said Gamepass/PC means that console sales dont matter as much to MS, I would give you that, but overall in Sony's case they are selling much more hardware and selling much more software. So the argument is pretty mute this gen. Perhaps it won't be the case next gen if MS sort out the MS PC Store as currently it's shite.