Don't do this to me. Gotta believe.
Probably not. Total volume of sales of the ports to PC is already a fraction of what they sell on PlayStation console, crossbuy would likely just eat into a hefty chunk of the PC sales.
It also creates kind of an issue with their PS5 software pricing strategy, since the PC versions definitely won't sell for $70 on Steam. You'd get a metric ton of PS owners buying the PC version (especially for games that are Day 1, which will most likely be some of the live-service titles) instead of the PS5 one, if it means they still get the PS5 one. That might result in more PC sales but it also means less overall revenue for Sony since they have to pay Valve a cut of those sales no matter what.
At most I think they'll provide PC versions to PS5 owners at a slight discount. So say a PS5 1P game gets an eventual port to PC a year or two later and it's $60 on Steam. For those who bought it on PS5, it'll just cost them $50 on Steam, something like that. Gotta keep in mind Sony needs the software profits off game sales way more than Microsoft does, they can't just afford to give a big chunk of that up with a one-time-buy-play-everywhere crossplay strategy. It's not financially viable for their model.