The main thing Valve has going for it is good will among the gaming population, which Facebo- Meta certainly doesn’t (to a stupid extent, IMO).
However, Zuckerberg said during the keynote that they were going to continue to sell hardware at or below cost in order to grow the space. I’m sure that’s somewhat of a business decision, but I honestly think Zuckerberg has a genuine interest in the technology and just wants to move it forward. While Valve could technically also sell at or below cost and hope to make it up with their Steam cut, they haven’t been willing to do that with any other hardware release.