Autodesk monopolizing the 3D tooling ecosystem and having entered an aggressive 'customer milking phase' via an overpriced subscription model about a decade ago played a very important part.
Yeah, I think this is definitely a good part of the driving force behind Blender's more recent successes.
That said, Adobe has been doing pretty much the same thing in all their spaces, and it hasn't spurred open-source competition in the same way (though plenty of proprietary competitors have been boosted by it)
