You're right in a way. The problem is that Mozilla seems unwilling to accept that that's their audience, so they keep trying to appeal to the 95%. If they would just double down on the "power user" audience they could make a killer browser. But instead they alienate those nitpicky users with pointless UI changes, breaking extensions, and so on.
Ignoring 95% of a uniform market to target the 5% of users who all have niche and conflicting preferences is a ridiculous strategy for stability, growth, and profitability.
I don't think there's any real future in catering to the most demanding users, most of which are completely unwilling to actually pay for a power user browser.
