It's bundled with lots of program installers, and Google push it heavily.

For people who don't particularly care about privacy, Firefox has nothing to offer and has a worse overall experience to Chrome.

I made the switch from Chrome to Firefox a year ago when for whatever reason Chrome started stalling. A year in, Containers all the rage, I still hate Firefox because its autocomplete sucks and if I type a/b in the search bar it tries to load http://a/b, what kind of logic is that? This isn't 1995. They literally fixed only this 2 versions ago.

Mozilla bug tracker has lots of bugs which are open for decades.

I live outside of US and I’m annoyed that Firefox does not fill addresses in forms, for example. Because Mozilla does not bother finishing this feature for the rest of the world.

Similarly they have released credit card auto fill recently, and again, US only.

That’s just one of many example.

I still use Firefox, but mostly because it’s hard to switch (reconfigure all extensions, get used to new UI etc).

People love brands. Most people thought the internet and Google were the same thing before Chrome even came out.