[sirclueless]

> E.g. if A patents X and some large company B wants to use X and A refuses, then B cannot use X even if they offer millions.

How does this situation improve in any way if X is a trade secret? Under what circumstance would company A be willing to accept payment to make X open, but not willing to license X as a protected patent?

It sounds like you'd be in exactly the same situation except that there would be a massive collective action problem trying to figure out how much the world should pay A to make the invention open and who should pay it, and also A and B would have multi-million-dollar incentives to engage in corporate espionage and counter-espionage that achieves no progress.