Immediate mode still exists and is usable to this day. The compatibility profile never went away.

JWZ implemented old-school OpenGL in a library on top of a more modern API, and I would entirely agree that's a good approach to compatibility. I'd have advocated for doing the same thing, just without calling everyone idiots.

Immediate mode makes no sense from a performance standpoint. But you can still use it in 2021 if you want. I believe it's still supported mostly for CAD programs which haven't changed their core software since the 80's

And if you like the immediate mode API, just use something like raylib's rgl[1] that emulates an immediate-mode API on modern OpenGL. Aside from performance benefits, you can port your code to GLES or WebGL, where immediate-mode isn't present.

[1] https://github.com/raysan5/raylib/blob/master/src/rlgl.h