Also, if they don't go FOSS, their users are living under a Sword of Damocles: At any point, they can choose to change everything, break everything, and your re

Also, if they don't go FOSS, their users are living under a Sword of Damocles: At any point, they can choose to change everything, break everything, and your recourse is one of a variety of impolite ways of saying you have no recourse. Being a customer doesn't save you, BTW: Giving them money insulates you not one whit from their decision that a course of action which destroys your whole setup will get them more money. This doesn't really change even if you have a contract: Unless you convince a thoroughly insane court to order some form of specific performance, the most you're entitled to is, essentially, a refund, maybe some punitive damages, and Wolfram no longer caring about you even to the extent they previously did.