It's because Apple is a (top) hardware company (and a software one) and they have years of experience at it. Meta is a software company; they could become a hardware company, but that doesn't happen in just a few years.
To be fair, Oculus was a $2 billion acquisition by Facebook in 2014. That should have brought them the talent needed to make hardware devices, despite being a software company at heart.
That’s not enough. Apple built its headset on top of 15 year mobile OS that has been ported across devices, custom built silicon, custom built cameras, screens, etc. Out of all the BigTech companies, Apple is the only one that does custom hardware at scale.