They did not always have 5% market share. iOS and Android pushed WebKit/Blink hard, and Mozilla did not quickly respond; the ecosystem has suffered as a result.
That's all true, but overall they've been steadily falling since 2010.
However I disagree with your view of the ecosystem. The web needs stability and consistency more than anything else. FF switching to Chromium would help with that. So many people have this knee jerk reaction of Chromium = Chrome = Google having total control. But don't understand the only reason Google has had this much control over Chromium is because no other major vendor used it. They were the biggest kid on the street. But now that MS moved in a few doors down, that's no longer true. Google has to acknowledge MS in a way they never did with Opera, Vivaldi, Brave, etc.. And the same thing would happen if FF switched to Chromium.
Idk about you, but having 3 of the 4 biggest vendors all being forced to collaborate and implement solutions supported by at least 1 of the others, is 1000000x better than having each do their own thing. You effectively go from a monarchy to some form of democracy.
However I disagree with your view of the ecosystem. The web needs stability and consistency more than anything else. FF switching to Chromium would help with that. So many people have this knee jerk reaction of Chromium = Chrome = Google having total control. But don't understand the only reason Google has had this much control over Chromium is because no other major vendor used it. They were the biggest kid on the street. But now that MS moved in a few doors down, that's no longer true. Google has to acknowledge MS in a way they never did with Opera, Vivaldi, Brave, etc.. And the same thing would happen if FF switched to Chromium.
Idk about you, but having 3 of the 4 biggest vendors all being forced to collaborate and implement solutions supported by at least 1 of the others, is 1000000x better than having each do their own thing. You effectively go from a monarchy to some form of democracy.