That does very directly answer the question of "why." You answered the opposite question: "why not." Neither of us know enough about BM's business model, plan

That does very directly answer the question of "why." You answered the opposite question: "why not." Neither of us know enough about BM's business model, plans, codebase, etc. to know whether open sourcing makes sense, and if so, how. I trust BM is doing something reasonable here. The only point is that the decision isn't obvious. In terms of 0.00001%, my experience is that bigger businesses care a lot about business continuity. I'm at a large organization, and it's cheaper to buy than build. At the same time, it's lower-risk to buy open-source. That's where things are trending.