I don't think they are as mentally tough as players from the past. They are certainly in better physical condition than players of the past. Imagine if we had 10 team leagues for a total of 20 teams of players in this physical condition. Imagine the baseball we would be seeing.
There were players in tremendous physical condition. But I think they were just that way without all the modern physical training regimens. Willie Mays, Hank Aaron, Earnie Banks, Mantle before that stupid sprinkler head took his legs....those guys were phenomenal physical specimens. You could have convinced me they were aliens from outer space. I would have believed it.