I agree. What we think of as the 50's was really the late fifties and early 60's. And frankly, I think that what we think of as the 60's was really the late sixties and early 70's. But even then, that is only when referencing pop culture.
When discussing things like auto racing or baseball or anything else more quantifiable, the decades line up more precicely.
I agree too. I graduated from high school in '69 and no one was into pot or drugs at the time, just booze. Did not see drugs or long hair (except on rock stars) until the early '70s.