Open models are a good thing. OpenAI was open until it became obvious that being open was not going to pay for training costs and wouldn't help them get a competitive edge. I'd bet that if Meta gets to a place where their model is in a similar position, they will also become more closed. But right now, Meta is open because that is what weakens and creates the most contrast with the other AI labs.

It's the same with any open source project: it starts open, then it becomes clear that maintaining it is not cheap and takes up a lot of time. The developers create a hosted/paid version to pay for their time, and to create an incentive to use the hosted/paid version they start releasing closed source enhancements. After that the open source version becomes marketing where new projects use the OSS version and then upgrade once their needs become more sophisticated.