This feels like fresh air compared to tons of tools written in Javascript and running in a browser.
If you are a professional then just buy more RAM.
That cockiness sounds familiar, and it was the reason why people moved from Java based IDE's to vscode/atom/sublime.
It used 10-20 megs of RAM and loaded in about 2 seconds on the computers of the era (about 10-15 years ago).
It wasn't very good, but that's beside the point :-) It wasn't bad because of the technology stack it was built from.
Sufficient extensibility does not require software to be terrible.