The way I see it, it's the only one in the top 5 that doesn't get set as the default out of the box on millions of devices. You have to be annoyed enough by the default option to even look for an alternative, and about 90% of the people don't reach that threshold.

How can people willingly use a browser from an ad company is beyond me. Of course that's a minority of the whole Chrome userbase, but a lot of people reading this comment use it fully knowing what Google is, and what its endgame with Chrome was from the day one.

In its early days, Firefox achieved significant marketshare because it was better and offered useful features that the incumbent browsers didn't.

Nowadays Firefox is just a poor Chrome knockoff with no distinguishing features. As a casual user who switches but is unaware of add-ons/etc, Firefox gives you nothing, so why would you switch?

Firefox can reinvent itself and regain marketshare by shipping actually useful features like built-in ad & distraction blocking, but chooses not to.

How much of this is because Cloudfare automatically classifying any Firefox as a bot and removing them from the statistics?

It’s also an underestimate because Firefox doesn’t always report itself via user agent (maybe not even by default, IIRC).