I'm not one to judge mosconis abilities because I've never seen him play. Well there is a recent thread with a video he did, but we all know it was scripted. It's pretty obvious he didn't "get tired". This leads me to question everything everyone has said about anyone I've heard from our history, even a legend.
Today's equipment is much harder to control cueball. Again this is just speculation, we would need a pool player of both generations to get the pudding. Nappy cloth makes it easy to whack balls pocket it and still get the rock to a parameter intended....and 5" buckets on nap is nothing compared to smaller pockets now days. The idea that someone can shoot without relying on a slight margin of error for cueball mobility, is like believing bigfoot exists.
Like other sports there are greats of an era but the can't compare to the guys of today. Todays players are monsters. Conditions have evolved making better players. Competition and the need to have to win just to eat has made some really good players all over the world.