Yeah I don't think they can. Just imagine if Wolverine releases next year with amazing graphics on the PS5 Pro. It'll give the PS5 Pro a real wow factor which Xbox will struggle to compete with. And the Pro will be the go to console for all third party games.
Microsoft are probably hoping that their services and the games their first party will release will be enough to pull many people into the ecosystem and sell consoles. But it doesn't look great tbh. Sony will have a console that will completely outclass theirs for third party and I think Sony will still remain more attractive for 1st party games to the majority of people, at least for the next few years or so.