Why do you think they don’t struggle with input latency? Because the non blocking nature built into the browser model is so powerful and you cannot get that with threads.
Are you sure that latency-sensitive parts are written in async JS instead of having a separate UI thread (pool)? I have no idea myself, but without knowing the details it's hard to argue. Note, that browsers themselves, are usually written in languages like C++ or Rust. They run JS, but aren't written in it
I disagree with the premise. I cannot imagine a better latency experience than blocking loop IDEs like VS6.
Which inputs are getting latency? The keyboard? The files?
> the non blocking nature
https://youtu.be/bzkRVzciAZg?si=BuBXxHTgN0OqsAhI