> I know Firefox's share of browser share has dwindled to almost nothing. I know sooner or later, well within my lifetime, it will be gone.

Market share appears to be hovering around 4%, which sounds small but that is still a massive amount of people, over 200 million users. It is even more impressive considering it doesn't have an OS with a large market share feeding it users, people overwhelmingly just use what is already installed. That's a huge number of users earned rather than inherited.