I don't see how they're devaluing other people's AI products.
If they make AI models free to use it makes OpenAI nearly valueless, which means that they can't survive and then sell Meta's competitors a better GenAI product than Meta can make themselves.
So basically since they don't make money directly on GenAI, it makes sense for them to release it for free so no one else can have something better, so they don't have to compete on GenAI abilities with their competitors.
Whether or not you think the "value" of AI products is proportional to their performance gap vs the next closest thing or not is up to you. Very interesting PG essay I read recently talks about the opposite of this (Superlinear returns) where if you're half as good as the next competitor, you don't get half the customers, you get 0.
The “0% of the cost” part is unique to software businesses because you can copy software so cheaply