First time I somked was in '82 so I guess it doesn't really count as the 60's or 70's but it comes close. Yeah, we used to get some kick ass buds back then but it was only every now and then. I think the big reason we're seeing such high potencies now, at least on a regular basis, is that a lot of weed is now grown indoors and in the U.S. (or Canada). Back then it was coming in from Mexico or points furthur south. Most likely is was grown outdoors as big cash crops. Money was the key, not growing premium weed. That's why there was a lot of seeds and the potency wasn't so great. Also, weed grown outdoors has a definite harvest time so if you were buying a bag in July it was most likely already 7-8 months old.

Now weed is grown by people who take pride in their work and are trying to produce the highest potency weed they can. They'll wait a little longer and take care that no male plants get mixed in. Hell, I haven't even seen a seed in at least 5 years. Plus, when its grown indoors the harvest time only depends on when it was planted, not the time of the year. So, you're more likely to be gettiung fresher weed.