a golden age of Amiga

[psxphill]

Indeed. One trick I've still yet to try, but I know must be possible, is to use HAM as a zero-cost polygon filler!

It was originally designed for that. However there is a cost as you need to clip polygons rather than use z sorting.

[psxphill]

I reality now, is that there isn't really an "official" AmigaOS... People can just use whatever they want to use.

You're half right, there is an official AmigaOS but people can use whatever they want.
 
"Official" in this case just means the name was licensed. It's no different to branded sports mechandise.