I don't think Firefox needs saving. Those who use it are active and committed to it.
Are they though? Are they so very committed they'll take all the crap Mozilla throws at them? Because Mozilla sure is trying their very best to get rid of Firefox users.
Don't be so sure. I stuck to Android though thick and thin since 2.1 or 2.2, but my next phone will be an iPhone, because I bloody had enough of their nonsense.
Firefox is harder to replace, if only because it's the only counter to Google's browser monopoly (so I consider it a moral imperative to keep using it), but if they keep reducing openness and end user control, I will eventually snap and abandon them. And if I'm nearing this point, then many have already passed it because I have a remarkable tolerance for shitty FOSS software. A family member already requested I throw out Firefox and install Chrome, and I complied because honestly, I can't fault them.
Yes, it's true that it's fairly anti-competitive behavior to only allow WebKit on iOS, but the painful truth here is that it stops Chrome from being spread around enough devices and taking over. Google cannot push Apple around anywhere near as easily.
Firefox is a literal drop in the bucket compared to that effort.