This can do more for gaming on the Mac than Apple's efforts combined.
The biggest problem is chicken and the egg. There is no high-end gaming hardware, there are few games, and there isn’t much demand for the kind of games Windows gets.
But without the hardware it’s not clear the games makes sense. And without the gamers it’s not clear porting makes sense. And without the hardware the gamers and the games won’t come.
Even if Apple released a 100% functional and performant Vulcan implementation tomorrow I seriously doubt it would make any real difference to the gaming market on the Mac.