I believe Sony claimed a lack of sales on PC as the reason they pulled out. Now dear user I ask you: What were they expecting?
Looking past their lack of games, their PC ports were notoriously rushed dogshit with every release. Almost every timed exclusive game that was released was a trainwreck and they did fuck all to advertise them. Most of these games that got released on PC were 2 years old and nobody gave a fuck about them, hell nobody gave a fuck about them when they were originally released. Even logistically speaking there is literally zero reason for anyone with even a low tier rig to own a console or buy their games when they don't run. Even looking at their catalogue now the only game I could see myself getting is Ghost of Tsushima when it goes like 50% off. Sony wanted to blame those dastardly PC players but the sad reality is that no-one gives a fuck about their faggotslop games, not even PS5 owners.