| Same with opencode and gemini, it's disgusting Codex (by openai ironically) seems to be the fastest/most-responsive, opens instantly and is written in rust but doesn't contain that many features Claude opens in around 3-4 seconds Opencode opens in 2 seconds Gemini-cli is an abomination which opens in around 16 second for me right now, and in 8 seconds on a fresh install Codex takes 50ms for reference... -- If their models are so good, why are they not rewriting their own react in cli bs to c++ or rust for 100x performance improvement (not kidding, it really is that much) |
If you build React in C++ and Rust, even if the framework is there, you'll likely need to write your components in C++/Rust. That is a difficult problem. There are actually libraries out there that allow you to build web UI with Rust, although they are for web (+ HTML/CSS) and not specifically CLI stuff.
So someone needs to create such a library that is properly maintained and such. And you'll likely develop slower in Rust compared to JS.
These companies don't see a point in doing that. So they just use whatever already exists.