I still use Firefox, it's still regularly updated and it still works very well. It pretty much does the job, regardless its number of users. It'll be dead when it won't receive updates anymore.
I don't understand what good can be done by considering it dead right now.
The one odd incompatible road here and there is also mostly there. These roads or the unpopular car we are speaking about only needs a few superficial tweaks. Nothing fundamental.
I know, I'm still rocking this car. It has the best windshield wipers of the market, for the very rainy roads.
It is also free so it's not like I'm making a big investment by picking it and risking it becomes irrelevant soon. Which I don't see coming, to be clear.
But still - what reality is there to face? At absolute worse we...switch browser in 10 years?