Personally, as an un-paid OSS maintainer, I chose to go get a job. Other's might choose different paths.

They can create business with closed source software. No one demanded of them to create Apache License software.

> So how should the maintainers eat?

If a corporation wants to build a business model around FLOSS, it's their responsibility to figure out how to do that. What they cannot do is abuse FLOSS licenses to pull bait-and-switch on their userbase to coerce them to meet their revenue targets.

They did figure it out. Contributors signed CLA and so their license change was absolutely legal and in line with what everyone agreed upon. When you started using the product, you should have known this.

See what I did there?