Honestly that's a very poor rationale. People should be choosing Firefox because it's a better product or a more ethical one (sadly they are doing a poor job at convincing us of that), not because we need to keep a competitor alive forever no matter what.
Regardless of the reason why, we're now reaping the fruits of Google's unchecked rampage across the browser space, what with Chromium/WebKit all but taking over. Mozilla continues to be starved for cash. Most Firefox users despise one of its only monetization strategies (selling advertisements). FF would be dead tomorrow if Yahoo (or whoever the default search engine is) pulled their funding. Mozilla is surrounded by rocks and hard places on all sides, what else can they do?
Yes, you can do that. But if you want it to be sustainable, you can't use that kind of line to convince people at large. And note that until Firefox 57, Firefox was not "marginally" inferior, it was substantially inferior in a number of metrics. They have improved since then, but it took them a very long time - you can't expect users to wait forever for you.
If we can't expect educated, tech-savvy users on HN to take the long view and support Mozilla, then I guess you're saying the game is already lost.
We might as well just make our peace that the age of an open internet and general-purpose computing is coming to an end. In future, we'll enjoy AOL 2.0 access on our Google Home Terminal Appliances.
https://robert.ocallahan.org/2014/08/choose-firefox-now-or-l...