Best "arguments" (they are really exceptions) for the "these pitchers today are wimps" thing are Nolan Ryan and Bob Feller. Feller was clocked in the upper 90s in the late 1940s with Army ordinance radar guns, which had just been invented.
Some guys are just freaks. Pitchers in the 1920s pitched in a manner similar to batting practice than today's max effort, max velocity style on every pitch.