If you haven't seen it, here is an article questioning whether Firefox has a future?
Just look at how Chrome has taken over as a favored browser. Safari continues to muddle along at about 5% market share, and Microsoft's new Edge browser hasn't even made a blip on the screen yet.
I'm not sure why Chrome has taken over, and the article mentions all browsers nowadays do pretty much the same thing, with some slight differences. I use Chrome, and started a few years ago because at that time it was the only browser that sandboxed Flash, which I had to use when listening to music while on my computer. Once started, apparently I'm a creature of habit and continue to use Chrome.
On my iPad and iPhone I use Safari, and find it is as good as Chrome, for all intents and purposes. But on my Macs and PCs I continue to use Chrome.