Check out this assembly programming series, it's less assembly code on the Amiga to get something on screen or getting mouse/keyboard input than with highlevel languages and APIs/frameworks today:
> I think the opposite is true because those machines were built around assembly programming.
This isn't true. It was extremely simple to get something work based on that tutorial, and to move to something more complex.
Doing that on an 80s 65xx-based machine would have been significantly more difficult, because that generations had significant limits in the coprocessors (AFAIK, the C64 could play music in games, but it was a workaround; it wasn't designed to do so).
Surely Amiga is easier, as the coprocessors were significantly more capable, but the parent based the discussion on C64 development.