I wish they hadn't maintained dominance as much as they have, but at the same time, IE being a non-standards compliant actor and Chrome at times including non-standard web features have brought out the best in Firefox: with IE, it forced Firefox to become a thing. With Chrome, it forced Firefox to streamline the cruft and become better.

Now at least, users have choice of what they deem the "best browser" to be and I honestly don't think they're inherently wrong for feeling that way. If someone uses Safari, Firefox, Chrome, Edge (though with that last one, I feel for them because it doesn't have the best tab recovery when Edge closes unexpectedly), or some derivative of any of the above, I think they're going to be reasonably okay.