After doing some Meta/Facebook VR development in my job the lack of popularity made increasingly more sense. In brief, they're both incredibly incompetent and transparently greedy.

I'm honestly baffled how they could spend so many tens of billions of dollars and have such bad software, it is completely bug ridden. You'll hit a bug, research it, and find out it's a major know bug for literal years they haven't fixed. They care so little that they couldn't bother to update the Oculus branding to Meta for over 3 years in various software tools and libraries.

Their greed might be more salient aspect preventing adoption, though. They transparently wanted to be the gatekeepers to everything "metaverse" related, a business model that is now explicitly illegal in the EU after years of being merely very sketchy. They are straight up hostile to anyone else trying to implement enterprise or business features. Concrete example: fleet management software, aka MDM. There are third party tools that are cheaper and much more featured than Meta's solution, but in the last year they've pushed hard to kick those third parties out of the ecosystem.

I could go on, but in short nobody in their right mind would build a major business on their ecosystem. They'd rather let Meta burn billions in R&D and come back later. Besides, not even Meta is able to make money in the area now.