Bullshit, a lot of Linux/Unix developers used Emacs in the 90's and early OO's.
I was there.
According to StackOverflow's 2019 developer survey [0], 50.7% of editors used VSCode, 25.4% used Vim. So that doesn't really support your claim that vi is a "mere footnote". 25% of market share isn't 50%, but it is still decent and more than a mere "footnote".
[0] https://insights.stackoverflow.com/survey/2019#development-e...
People overestimate the value of massive community and apply a winner takes all mentality too often. You don't need a giant community, and almost by definition giant communities tend to have a lower average user quality leading to lower quality of libraries and support (looking at you JS ecosystem).
They think the world revolutes around them with JS and hip editors while in the end they are the utter minority in serious IT/dev environments.
I'd like to think that too, but the sad fact is that most developers these days use VSCode. It is the new hotness that killed Emacs and vi. Emacs and vi are both mere footnotes compared to VSCode in terms of market and mind share, and even Eclipse has been largely supplanted within its niche by the far easier IntelliJ suite.
I suppose vi and Emacs will be around as long as they have diehards still using them, but they're not capturing new users' hearts and minds like they used to. Most professional developers I've met hear Emacs and think it's something that last ran on dusty old DEC iron -- and that includes people who worked at DEC in the 80s! The fact that Emacs is still maintained and runs on modern systems came as a genuine surprise to them.
Emacs and vi held on for as long as they did because there was a significant contingent of developers and technical people still familiar with a traditional Unix environment up until the 2000s or so. As some of these people aged out of the work force, they were replaced by an even larger contingent of younger developers, who only ever grew up with Windows and Mac, and have a reasonable expectation that programs work the Windows and Mac way. By and large they don't even have much interest in Linux on the desktop. Linux is for servers/the cloud. Their dev workstation is a Mac. And Emacs and vi are relics from the before times, whose 1970s UIs just aren't worth grappling with because there are better options available. Those are the people Emacs has to reach if it is to stay relevant. Which means that one way or another it will be "modernized" whether we like it or not.