If it's open source then anyone can fork, right? So sell the extension, fork it, publish a new non-shitty version, and let users know via some non-official means. The only losers are the ignorant people who don't switch and the people you sold it to.
I mean, this is what happened with MariaDB, and over the years more distros have outright replaced MySQL with MariaDB. He made a lot of money selling MySQL too.
I don't condone this idea for browser plugins because the userbase for plugins are usually install and forget. I don't think most devs spend their time reading all the release notes of every plugin they install.
When you install a database server / engine, you take time to figure out if it's the one you want or not. You research the company and other companies using the product.
