Meta has the massive advantage of not needing to sell the AI. The primary purpose of Llama is to make Facebook, Instagram, Whatsapp, Quest etc. better (well, "better" from the perspective of the company). It is basically an internal tool. So just like React, Cassandra, PyTorch, GraphQL, HHVM and all of their other open source work they benefit from sharing it with the rest of the world. There is very little incremental cost, and they get to generate massive goodwill and attract talent because of it.