RB, I too was pondering this part of the equation and did a little surface scratching to see if this true as well.I believe that strikeouts per innings are at an all time high, and I expect that walks per inning are also at at least 50 year highs
1970 1 bb every 9.6 AB - 1 K every 5.9 AB
1980 1 bb every 11 AB - 1 K every 7.1 AB
1990 1 bb every 10.3 AB - 1 K every 5.9 AB
2001 1 bb every 9.7 AB - 1 K every 5.2 AB
In that span the average BB occured every 10.22 AB and a K every 6 AB.
I think that contracts and the fear of ruining an asset plays into the coddling as well.
You're right that pitchers of the 60's often had almost NFL running back careers, short and burning bright.
Koufax retired at 30
Drysdale retired at 32
Malony retired at 31
The amount of pitchers who achieve a complete game is getting smaller at a prodigious rate.
1960-1969 - 598 seasons with 5 complete games - high Marichael 30 -1968
1970-1979 - 610 seasons with 5 complete games - high 30 3 times.
1980-1989 - 437 seasons with 5 complete games - high Langford 28 -1980
1990-1999 - 147 seasons with 5 complete games - high 15 twice
2000 - 2001 13 players high of 9 by David Wells.