More plausible scenario is them becoming an abandonware, but even in those cases the community can carry the torch.
The impact of developer good will is difficult to measure, so I don't attempt it. Redis burned community good will so badly with their relicensing that several forks rapidly emerged. Seemed like a predictably poor decision to me.
I also don't want to pick favorite companies, because it's subjective, companies can change strategies or even sell projects off. What if Meta decided to sell React to a patent-troll-like company instead of just abandoning it?
[1] https://alexsci.com/relicensing-monitor/projects/kubernetes/
There are valid reasons to have a CLA: confirmation that your contributions are not encumbered by an employer contract is a good one. What there is rarely an excuse for is a copyright assignment, which often gets bundled into a CLA.
The only non-nefarious example of copyright assignment that I can think of is the FSF, but only because they have such a strong record on software freedom.