Brave is a weird example because it included several former Gecko engineers when it started up, so Brave not using Gecko did have some sort of material impact o

Brave is a weird example because it included several former Gecko engineers when it started up, so Brave not using Gecko did have some sort of material impact on Gecko. I have no idea if you can quantify how much "damage" was done, but some can be assumed. "Fast" is the second priority listed in Brave's webpage ("Secure, Fast, & Private"), so it is very easy to assume that it was one of their reasons for making a fork of a browser in the first place. It is more than fair to criticize them for taking the ("paved with bad intentions") easy road in that stated priority rather than accepting the true engineering challenge of doing that work on the underdog engine in current last place. (The basic through line of lamenting that they didn't use Gecko: If they had succeeded in that challenge, they would have won a lot more acclaim and done a lot more overall good for the web than anything they have done in forking Blink.)