Probably better, but the callback hell stems from a broken up control flow; where we cannot read / understand what's going on with a linear (top to bottom) scan

Probably better, but the callback hell stems from a broken up control flow; where we cannot read / understand what's going on with a linear (top to bottom) scan of the source code (even for small sections of code). I think programming where we have state and things can happen at any time, where programs wait for events or something similar has proven to be difficult to write/understand/maintain. The 30+ years it has taken to write the (unfinished) Herd micro-kernel is a good example.