I think the only way MS knows how to make money is lock someone into an ecosystem. I think their next attempt should be a closed source lean checker that has will have proprietary code for NL -> lean formalization checker.
Altruism happens usually among members of a tightly knit group, like family members or soldiers of a given unit. Teachers sacrificinng their life to save children. FOSS-developers, are they really producing software out of altruism? Maybe some of them are but it is hard for us to know whether that is so or not.
They mostly start the software because they themselves want to have it.
When they start working mostly for other people's needs, I think it's a mix of altruism, pride and probably enjoying the work.
But the truth is - so do I - as a humble contributor to a document, test, bug fix, or feature add to a FOSS project - where's the beef?
Totally altruistic!