[closedloop129]

That doesn't explain why the community didn't step up much much more and brought the development to new heights.

What is holding back Java developers from using their Java language to adapt the IDE written in Java that they daily use? If their boss told them to implement a feature, they would do that. But they don't implement the feature when they need it.

[bitwize]

It's a relative doddle to make changes or write an extension to Emacs or even a Smalltalk system like Pharo.

Eclipse, by comparison, is complicated. There's a whole lot of scaffolding and frameworkshit that goes into building an IDE that works the way Eclipse does, and that greatly increases the friction of extending it. Plus Eclipse, like most Java programs, is not really a live system that can be extended and changed as you run it; both Emacs and Smalltalk are. Not being live further increases friction. End users aren't really supposed to extend Eclipse themselves, just download and install prebuilt extensions, and this is accounted for in its design.

Visual Studio Code has the same problem. It may be somewhat easier to extend than Eclipse, and it was certainly intended to be so, but doing everything in webshit didn't really address the fundamental issue.