If a company is built on hosting redis - and is now unviable, they should be pretty incentivized to fork the previous version and maintain it themselves. Isn’t that the power of open source?

I doubt there were many (if any) non-AWS businesses that were affected. To earn a profit you need to continue to work, I don’t feel bad when a corporation is negatively affected after their leeching or rent seeking is disturbed. Even if it was previously acceptable behavior.