Those are some good shots (pun intended). I'm not super familiar with the .243. Over here in the US it's mostly .30-06 and .30-.30 when it comes to deer hunting. Perhaps a few .270's thrown in there. It appears though after doing a quick Google search that the .243 is way more common than I realized.
It's a pretty common calibre, shoots a flat trajectory and with a lot of energy imparted into the target. I've shot many a kangaroo and deer with it although for the larger game .308 is better despite its less flat flight path. We have those other calibres you mention but they are becoming less popular.
That is interesting. I guess it just makes sense that things would evolve.
New and better things come along all the time I guess. I've done a lot of shooting (hunting) with a 30-06, .243, .308, .22-250, .223, 300WM and others...it all depends on the situation.