Mozilla Firefox Did Not Die, It Got Killed
A series of bad policies, "dick moves" (or alienating moves) and self-inflicted scandals for nearly a decade left Chrome (or its 'siblings') with a near-monopoly:
Judging by this month's numbers from statCounter, Mozilla is almost dead. It outsourced its source code to proprietary prisons (of Microsoft), Firefox market share became low enough for Web developers to ignore (or not test URLs with), and there seems to be no real direction. The official Firefox blog keeps promoting proprietary social control media platforms while name-dropping "hey hi" (slop).
Those who still look for a non-Chrome non-spyware-disguised-as-browser should take a look at LibreWolf, which is not too difficult to install. Unlike Firefox, its source code is not controlled by Microsoft and its developers are not indebted to Google.
To me it'll always look like Mozilla got killed by its sponsors, especially Google, which had a conflict of interest as a sponsor. Much like Microsoft in the Linux Foundation. █