Hi,
My last Linux distribution was Suse 11 or so (at the time they were a kind of de facto standard over here in Germany for people who wanted to have a good distribution that was reasonably user-friendly and easy to install - nevertheless, the console would still rear its ugly head from time to time if you basically pressed the wrong button - it was alright for me as a DOS veteran and experience with typing stuff instead of clicking on icons but in those days Linux definitely was not anything to be let loose on Joe or Joanne Average User - I do not know what things are like today - unfortunately I do not really have time for or feel like formatting my hard disk every couple of days in order to try out a new system - am quite happy with Win 10 apart from the default software midi that was introduced after Win7 - I just prefer my hardware Roland SC-55s, SCB-7, and MT-32 for the old classics 
- by the way, I also find that with Win7+ it is much easier to get old stuff to run than it used to be with WinXP but maybe I have just been lucky - alright, for some games you need tricks like compatibility modes or installing them in safe mode (Win10 - e.g. Comanche 4) but I am still quite impressed with how much of my old stuff still works).
As far as either left or right mouse button for ‘left-clicking’ was concerned, I was thinking of things like CDE or OpenStep. And if my memory is not completely clouded, I think it also was possible with KDE 3.x but I am not sure.
As far as I am concerned, my favourite Linux desktop was KDE (3.x). I never really warmed to Gnome and KDE 4.x took a while for maturing.
Anyway, enough waffling/spamming - before Ron boots me off this forum ;-).
Cheers