I just find it hard to believe that it's possible to be significantly faster than Chrome, to the degree that it would be a notable differentiation--especially when the apps Firefox is loading are largely (again) controlled by their adversaries--Google, Facebook, Netflix, Microsoft. For an extreme (albeit non-performance issue) case, look at Widevine. What was Mozilla realistically supposed to do there?
> They seem more interested in playing the role of a nonprofit quasi-startup and social issues advocate than maintainer of the most viable and valuable open source browser.
I think this is where I disagree with most of the people who say Mozilla should stick to Firefox. I don't think you can make Firefox sufficiently "better" than Chrome engineering-wise--certainly not to the degree where people would notice, and I absolutely don't think you could do it with the owners of the most popular web properties having an incentive to work against you, most of whom have a competing web browser.
The problem was/is, they take the money their primary product brings in and invest it into some arguably bad, or at least irrelevant, ideas rather than just reinvesting most of it into Firefox and services consistent with what Firefox represents to users. Part of the reason Firefox lost so much market share was that for several years it had been seriously neglected (presumably so that Mozilla could focus on those arguably bad ideas) while the competition continued to improve. (hint: the #1 metric is performance) They seem more interested in playing the role of a nonprofit quasi-startup and social issues advocate than maintainer of the most viable and valuable open source browser.