Okay, but what if after all this legal action Mozilla decides that it's no longer worth serving the privacy conscious crowd? Which browser will you use then?
Things only happen in a desirable direction if there is dialogue. Linus made the decision about making Linux GPL but he is against aggressive enforcement. He thinks it's much smarter to go and slowly convince the offending parties that it's in their benefit.
Turning the feature on by default is bad, but I don't think that legal complaints are the way to go as well as the aggressive tone of NOYB. Firefox is the only browser developed and maintained professionally which has the potential of offering some privacy on the web. Given the importance of web browsers volunteer work just won't cut it with the amount of features and security concerns that a browser needs.
NOYB would've done much better by talking to Mozilla directly and advocating for them to do the right thing going for a legal complaint as the final nuclear option. If the was the case, then good that there's a complaint, but the article does not indicate the any of this happened.
Sorry, but I don't believe that's realistic. Devs need to be paid. To be paid they need execs. Donations might sustain a small project, but not a web browser. Linux is developed primarily by devs employed by the big corporations. It would never survive on donations and volunteer labour. Same for Firefox. A browser is too complicated to be run as a GitHub project.