There's no getting around the fact that developing AR technology requires substantial investment in R&D. Only companies such as Facebook, ones that employ some of the best engineers and also have a strong incentive to make that investment, are able to pull it off.

Whatever product comes out of Facebook under its current business model will be optimized for serving ads. Not necessarily serving the user.

This in itself is not bad, as it will still stimulate the growth of an ecosystem where developers can create products with different business models.