I'm saying all of this as a FF diehard since before it was named FF... right up until today. I'll use FF until they pry it from my fingers.
Back in the IE6 vs. FF days... IE was inferior in every way. IE was crashy, had no tabs, pathetic/hostile developer tools, insecure, poor support for open web standards, etc.
But today?
The difference is that Chrome is really good, with great developer tools. It's a great user experience.
FF only really wins in terms of better extension API (allowing things like uBlock Origin) and the "moral superiority" of not being created by an advertising company, and serving as a bulwark against a browser engine monoculture. And among real privacy diehards, they're probably using something like PiHole which makes uBO perhaps superfluous for them.
But it doesn't out that even developers who should know better apparently DGAF about those things.