Firefox was already statistically irrelevant 5 years ago. On our dashboard, a global e-commerce site with billions of views per year, it's not even in the top 10. Even regional browsers sometimes surpass it.

Firefox is also no longer a developer-default browser. This too has been true for years now.

There's very little Mozilla can do about it. Chrome and Safari are big because they're shipped as a default to platforms with billions of users. And the web works well on both of those browsers. It's not an engineering problem. You can't improve Firefox and expect market share to rise.

It's pretty much a done deal, and Microsoft (as well as Brave) using Chromium cemented that deal.