Delphi and C++ builder should have been ported to Linux and the BSDs by 2001.
They hitched their wagon to Windows and are now almost a footnote in history.
Come to think of it, almost all Windows only applications faced the same fate.
My first serious language was Turbo Pascal 3.0. When Delphi came out, I jumped on board. My first programming job was as a Delphi programmer, starting with Delphi 1, switching to Java after Delphi 5 Enterprise. Delphi, and even C++ Builder were IDEs geared toward producing desktop client-server applications. If you were building web apps Java was the place to be.
Kylix never mattered, because Linux desktop applications didn't matter, generally speaking, so it never became profitable. Linux as an alternative to Solaris on servers was a huge deal though, and is now nearly ubiquitous. But again, Delphi came very late to the web application game.
The way the web changed customer facing software was amazing at the time.
No. I can't remember that ever being a thing, I've no idea where you got that idea from.
My point however is that when I started working in IT I was the only one at the places where I worked who used something other than Windows whenever possible and also advocated for it.
Then there was a change. And as far as I can see that change started with screencasting and as far as I saw, the first widely popular screencasts that existed was Rails, created mostly by 37 Signals (now Basecamp I guess) and other Rails devs/enthusiasts.
I might be wrong about this but I feel fairly certain these guys drove a lot of the change in peoples and organisations attitude to alternative OSes.
Also: for a long time it seemed Linux adoption was also lower in less wealthy countries as using unlicensed versions of Windows are much more accepted there.
As it turns out, the remaining 78% users (taking out the usual 2% from Steam surveys) that cared about POSIX tooling, were happy to use SUA, cygwin, mingw, Virtual Box, VMWare for their needs, and now have WSL in the box anyway.
That is an extremely good point that somehow escaped me.
Besides, the early 2000s were the era of the “this is the year of Desktop Linux” tech articles. Of course that never materialized and Linux desktop is still pretty niche. So I don’t really see how lack of Linux support had anything to do with it.
I remember having a "ruh-oh!" moment when a junior dev showed me his latest DHTML web page that did something we'd previously been doing in VB. The sudden realisation that this was significant and I'd better get on with learning it or be left behind was painful. The urge to continue dismissing the web as a good information source but not somewhere you did things was strong.
And C++ builder was never ported.