The vast majority people who use web browsers have literally zero knowledge, awareness, or interest in these things. What actually seems to have happened, is that a long time ago now, their techy friends recommended they use Firefox instead of IE. Then those techy friends recommended Chrome because it was even better. Now it's arguably the case that Chrome and Firefox are equivalent from a non-techy standpoint, but non-techies don't want to move browsers over and over. That large audience is largely lost to Firefox until there there are big enough
practical downsides to Chrome or upsides to Firefox.
As it stands now, even if techy people, who might be put off by the things you mention, were to be made perfectly happy again, if they recommend Firefox without a significant practical justification, non-techy people simply will not change from Chrome back to Firefox again.
Importantly, more and more people have just grown up with Chrome, never having used Firefox or IE even once. Even if Firefox stays as good as Chrome, more and more people will start their web browsing experience never having considered Firefox and just always having organically used Chrome. This alone will lead to Firefox losing market share over time, even if all existing Firefox users keep using it and loving it.
In my mind, it's clear that the reasons Firefox lost market-share are technical/practical, and the way it might regain market-share is also technical/practical improvements. That will be hard though, especially given Firefox would probably need technical/practical dominance on Android as well as on traditional computers.