I was just reading https://thenewstack.io/what-happens-to-relicensed-open-source-projects-and-their-forks/, about the contributor dynamics of formerly-open-source projects that were closed down, and their community forks.
There's not very much concrete data in this article, but it does suggest something very interesting: that there seems to have been a set of people who *wanted* to contribute to a project, but were somehow unable to when it was under corp-centralized stewardship, and only became able to when there was a multi-stakeholder fork.
Clearly the license was not originally a problem. So what was? Was the governance of the original project hostile to external contributors on an organizational level?