It's all funded by enterprise licenses.
b) They give things free to drive up adoption. For example, I don't think it will be free anymore if it was as popular as GitHub. Since that would not be sustainable.
IMO, it's a poor decision by gitlab to give things out for free. Instead of innovating on features, they try to keep it cheap.
(I say the same for all companies. Charge money for your product. If people see value, they will pay.)