I honestly don't understand why we lose IDEs and editors.

I understand that software requires people maintaining it, but my point is more that I still don't understand the why.

We have some functionality, a lot of which could be re-used in editors and IDEs. But people rarely share stuff. They like to re-implement things. Again and again and again. This is not logical to me.

I'd like to have one editor that does EVERYTHING, but in a modular way so people decide what that editor can do. People could then just maintain one cohesive, feature-rich code base rather than each one duplicating what is already available in another IDE/editor.