I disagree with the premise. I cannot imagine a better latency experience than blocking loop IDEs like VS6.
replyWhich inputs are getting latency? The keyboard? The files?
> the non blocking nature
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
replyYes they are, the UI layer is mostly JS, outside the rendering and layout engines.
replyIf you implement threads and code that reacts to an input queue (e.g. PostMessage, queue_push, mq_send, ...), you've implemented (probably a bad version of) async threads. And yes, that's exactly what Windows 1.0 did and what made it great.
replyBut God help you if you have to change the code. Async threads are a way to organize it and make it workable for humans.