Google's search deal with Mozilla is such a sizeable portion of its overall income that without it, Firefox would struggle to compete - or even survive,
What does it matter? They all rely on Mozilla to do the hard work - maintenance and keeping up with web standards, and then just slap a couple of features and customizations on top of it. If Mozilla dies the current forks are dead in the water.
The problem isn’t the existence of forks, it’s rather how many developers are behind them. Mozilla has around 750 employees, so I’d guess maybe around 500 full-time devs work on Firefox. Tor Browser and such have significantly fewer contributors, who only do this stuff in their free time.
There are already several forks that are fairly popular.
What does it matter? They all rely on Mozilla to do the hard work - maintenance and keeping up with web standards, and then just slap a couple of features and customizations on top of it. If Mozilla dies the current forks are dead in the water.
The problem isn’t the existence of forks, it’s rather how many developers are behind them. Mozilla has around 750 employees, so I’d guess maybe around 500 full-time devs work on Firefox. Tor Browser and such have significantly fewer contributors, who only do this stuff in their free time.