I think the distinguishing question is, "Is the company's software a tool used to fulfill the company's goals, or is the software itself the goal of the company

I think the distinguishing question is, "Is the company's software a tool used to fulfill the company's goals, or is the software itself the goal of the company?" If your answer is the latter, then you have more problems in store than open-source viability. You aren't genuinely testing/dogfooding your product. Your product goals will trend away from real customer value and toward implementation convenience, self-compatibility, 3rd-party incompatibility, and a closed-minded product vision. The only way to keep this business model viable is to monopolize your market. But will it be you monopolizing, or will it be FAANG?