Hang on... .do you honestly think these guys were throwing 90+ mph in the 60's for 16 innings? Chances are they were throwing low to mid 80s at best during starts at their peak. The average fastball in the 80's was 88 mph, and was over 92 as of 2014. Unfortunately there's no way to know for sure what the average was back then since they never used radar at all, but common sense tells you they don't compare to today's velo, or even the velo from 30 years ago and after 16 innings it's very likely that 75mph is not some wild guess designed to make them appear weak.
Also, yes there were great hitters in the lineups, but they were great hitters relative to their era. Pitchers then are undoubtedly "worse" then vs today's arms, but in their own era they were dominant, because as a whole, both the pitching and hitting pools were shallower than today. That's just how it is in all sports.