I was the dev lead for a medium size company where we depended on a software platform by a solo dev. We made up 60%+ of his revenue. We insisted as part of the contract that he put his code in escrow and that we had the right to a copy of the code under certain conditions.

But no, I wouldn’t as a person who hypothetically made buying decisions. It’s the “IBM problem” that non dominant companies face. “No one ever got fired for buying IBM”.