Getting a computer to do work for me has always taken a hell lot of time and effort as well.
The complexity is mainly in the interface, a computer imho needs several controllers to work as an instrument and you’ll end up with a pretty complex system, where the interaction elements are spread out over several input/output devices: screen, mouse, keyboard, external controllers, except maybe with some highly integrated and software specific solutions like Push or Machine.
I find them pretty hard to deal with in a live situation and the final system ends up being very complex and thus prone to errors.
There’s things where computers totally shine: for example (but not limited to) anything that has to do with editing, managing of big chunks of data, tasks where you get the benefit from having a big screen and a precise interaction instrument like a mouse and so on. That’s what the computers (as in keyboard/screen/mouse computers) where designed for in the first place, to manage, edit and process big amounts of data. This is also the reason why many apps that come from the desktop world, are totally crappy on a tablet device.
Anyway, a DAW is basically that, an instrument to deal with big chunks of audio data and organize and process these in various ways. The border to a live-performance system that works with MIDI sequences and audio snippets of course is blurred, that’s why Ableton Live or Bitwig make sense.
My point about general-purpose computers being most of the time half ass is that they are often a very inefficient solution to a simple problem. The reason we need all those controllers/audio/MIDI interfaces is that the computer itself, in its standard configuration, is totally not fit for what you need it to do, so people need to engineer something “around” it to fill in the gaps.