The linked page seems to indicate Chrome is leading because people are browsing on their Android phones. So it would seem if Mozilla should concentrate on anything it would be improving the mobile experience.
That is actually the one area where Firefox is already better for me, because of extension support. Having an ad blocker on mobile devices is priceless.
I've been waiting for working and full printing support something like https://www.smashingmagazine.com/2015/01/designing-for-print... for years now. Printing articles from the browser is the same pain as 10 years ago.
But yes this is not as fancy as voice search or file sharing (or their single sign on, identity and all the other failed stuff).
Mozilla has been a vehicle for people who play out their tech and political dreams and then move on. And FF is crumbling all the way.
But this misery is soon over, we're in the end game of Firefox.
https://www.w3counter.com/globalstats.php
(Written from FF - a browser I've used since Mosaic)