Mozilla decided at some point to kill extensions - whether following Google Chrome or of its own volition. It took an axe to its ecosystem by disablign the loading of anything external other than WebExtensions - and note that it's just an artificial disabling, as internally, Firefox is still basically some bundled "extensions" over a C++ core.

And now there's the "manifest v3" change, and making people jump through hoops to be on AMO.

This is very sad, almost as much as the internal governance over there.