I am sure they have thought about, but decided against it. However, I think, what they should have done is have an open-sourced language runtime, and closed so

I am sure they have thought about, but decided against it. However, I think, what they should have done is have an open-sourced language runtime, and closed source some subset of the libraries. In other words, keep eco-system open-sourced (and also protected from patent abuse), while maintaining some libraries closed source. Perhaps, Wolfram believes that the competitive/money making advantage is in the engine, not in the libraries. But if that's the case, then the open source competition is closer to beating it, than we think.