They could totally dominate both markets, if they wished, for not that much more investment. A G2 headset is already developed, licence that, then make it work with their own ecosystem. Almost all would buy that, and that still leaves Quest/Quest 2 to dominate the standalone market.
They have the resources - this is Facebook after all.
Couldn't agree more, though Facebook have alienated some users with their gating of all social features via a Facebook account. I don't have a facebook account for various reasons, though mainly for privacy. My beef with using facebook for social features is it requires your real name to be visible to your friends list. I like to keep my gaming profile separate from my real-life profile. Saves having trolls doxxing you or following you around the net hassling you.