Re: 70+ match wins in a single season？
I think this kind of wins are not as possible today due to this slow hardcourts. Before you had clay, but clay doesn't beat up the body. And then grass, points tend to be quicker and grass is also less on the body.
During Martina's days, Aussie was on grass, and the hardcourts were mainly pre-US Open which were fast. there were no slow hardcourts.