I’ve got a stick in my pickup and would never drive anything else. I spent a good deal of time in Namibia where they drive on the right, and that gives you a whole new perspective on driving a standard transmission - shifting with the left hand takes a bit to get used to. Gear pattern and pedal layout are the same, but the stick’s on the wrong damn side! Where I really noticed it was when you down-shifting to turn and want to put on the signal at the same time - you need two left hands...
...while approaching a busy round-about and trying to remember the right-of-ways, and remember to look LEFT! I drove a stick in New Zealand quite a bit.
I have sometimes wondered about that (I guess I have too much time on my hands).
One approach to RHD cars that appeals to the engineering mind is simply to flip the blueprints, so the gear pattern and pedal layouts would be mirror imaged about the centerline. Come to think of it, maybe the gauge faces and and legends should be, too. ≤}B^)
I guess ergonomics does enter into it at some point, though, spoiling the sweet symmetry of the strictly engineering approach.