By offering a subset of their capabilities, with key features implemented in a multi-process architecture, using plenty of C++ and Rust written modules.
Additionally the terminal has to use WebGL to achieve usable performance.
key features implemented in a multi-process architecture, using plenty of C++ and Rust written modules
Which is exactly the point—the UI is written in HTML/CSS, not the native platform language, and the high-performance modules are written in C++ and Rust, also not the native platform language.
Yes, web app programming sucks. But a web framework UI that communicates with a native backend has a lot of advantages when compared with the actual alternatives I could use instead. The web has gotten orders of magnitude more investment in tools, and it shows.
This point feels as though the author intends it to function as a 'defeater' -- C++ and Rust are used, therefore VSCode is a bad example (as a neighbor post says, an 'exception that proves the rule'.)
I invite you to consider that the converse may be true: if you can keep things performant by RIIR or even C++, it makes a great case that desktop apps should resemble web apps, with a native backend talking to a JS/CSS/HTML frontend. It does not function as a cautionary tale, but as a compelling proof-of-concept.
Additionally the terminal has to use WebGL to achieve usable performance.