Mozilla Firefox Won't Survive and Many Sites Don't Work With It (Compatibility Abandoned)
Updated yesterday afternoon (rolling over to November):
Using a decent and actively-maintained derivative of Mozilla Firefox is no longer enough. Heck, even using the "original" and trademarked Mozilla Firefox isn't enough anymore. There are many sites so stubborn that they don't get tested for anything other than Chrome and Chrome-like (or Chromium-based) Web browsers. Some of those are critical sites. Sure, you can do some things on paper - as in fill out forms by hand - but this isn't pleasant and it's not cheap.
Mozilla Firefox is basically dying. In the US, once Mozilla Firefox falls below 2%, government sites needn't assure support for it anymore. This is the latest from analytics.usa.gov:
There's a kind of a "Death Loop" here; if sites deem Firefox unworthy of supporting, then many Firefox users will stop using Firefox. That, in turn, means Firefox loses even more market share and then more sites stop bothering ensuring support for Firefox.
The Web has become monocultural. A lot of HTTP/S is little but a transport layer for a single GAFAM browser (or codebase). Based on recent reports, Google et al will soon take another step towards blocking HTTP traffic, mandating that all Web connections go through a cartel of CAs. That begets centralised censorship of the entire Web. This is what they want. █