There’s absolutely no guarantee that Sony and Nintendo would allow Game Pass on their consoles just because Microsoft stops producing consoles. In fact I’d say it’s still unlikely. And Microsoft would then be at their mercy which is far from an ideal situation.
I do think you are right about Microsoft being done with losing money subsidizing console hardware. But that just means the hardware will be more expensive, not that they will stop producing consoles. There’s no reason to. They have already ”raised” the price by making the Series X almost exclusively available in Forza bundles. They don’t need to outsell Sony to still have a meaningful console presence.