Only if SNY was totally backed into a corner, which they certainly aren't yet.
The problem is profits, and XB wins that game big time if GP ends up on PS consoles.
If that wasn't the case, SNY would've allowed it already. Like cross play.
That would come. Sony are already making money with every PS5 disc edition sold.
Xbox hardware would be squeezed out and made redundant. Sony would control the store.
So if making money on hardware is so great, then why would MS disregard hardware?
MS hates the 'most' profitable portions of gaming? MS hates control?
The only GP on PS5 strategy that makes any sense right now for SNY, though sleezy, would be to agree before MS makes any more acquisitions, which includes having MS stop selling XB hardware anymore. Then do what some of the tech companies have done to cripple their competitors and say, 'XB is bad because reasons, so we're kicking/banning GP off PS5 entirely'.