Seems to be a little bit of misinterpretation of what I meant on a few levels. I was speaking of 'then' not now, in so far as the AmigaOS being fully established and a main player in that (past) time.
Also, I was not referring to the current AmigaOS being re-engineered to supplant today's Linux - again, I was speaking of a 'what if' of back then, not now.
In general, I was hypothesizing on something many of us do: What if the OS had been allowed to evolve to the point of say, Windows, to a fully mature, fully realized product, used by millions?
That would certainly make it a little more difficult for any third or fourth party OS to be introduced into the mix - much as it is difficult for one to be introduced now. That's all I was really referring to - 'then' not 'now'.
My approach to creating a new OS for the Amiga would be to start from scratch, as if neither Windows or Linux existed. (And also, still keeping in mind what most modern computer users expect in the least from their computers - what I'll call the 'common courtesies'.)
But to me, neither Windows nor Linux are the 'be all' and 'end all' of OSes. Personally, I prefer command line interfaces, but I realize the general public requires GUIs. I don't swear by either of them, although I often do swear at them!