Earlier quoted context omitted.
Firefox was quality wise on a higher level than IE 4, and it didn't loose any of that. IE got better over the years, made a massive step forward with Edge and now again with Chromium based Edge. And finally MS is approaching Firefox in terms of quality. What kind of funding does MS have, compared to Firefox? And still they are outsourcing the hardest part of browser development, while Mozilla is still doing it on the…
I'm not quite sure how this addresses what I wrote. Three things: Firefox got popular when they listened to users and made a product people wanted. They did this despite fierce competition from a huge monopolistic company with quite a locked in and anticompetitive platform. And today they make something crazy like a half billion dollars a year from firefox, they have enough resources to make a competitive browser.
Also, they still make a competetive browser, as I laid out. Just the fact that some of the competition has improved massively (but by no means all of it) doesn't change that.