You are right. The Lydiard, Cerutty, and Bowerman eras were before I was born and they were indeed better. That is true. There were always "good eras" in training.
Sadly for me and my friend, we happened to be at our prime (mid to late 1990s) during an era when:
a) America sucked
b) we all ran low-mileage (50-70 miles a week in college)
c) we raced every workout "all-out" because we were usually hanging on for dear life
d) we didn't do any strength, core, or stretching at all
e) we did a ton of short intervals to train for the 5000m
f) our best nutrition was spaghetti feeds, Gatorade, and bagels (and zero protein)
g) we ran our easy days way, way too fast and never really recovered
and h) we didn't start running until we were in high school at the earliest.
I know that today, none of these eight factors is considered "smart training" anymore. That is what he and I were commenting on.
The kids of today are doing it the right way and I respect (and envy) that. Modern training is much better as reflected by the huge jump in performance at every level. The proof is in the pudding, the 1990s sucked compared to today. I am fine admitting that.