I have heard that weed from the 70s era only had ~2% THC where now at least dispensary grade can hit 20% to 25% THC. That could well be due to the drug war selecting for more powerful highs in smaller packages, but i would think that would also reduce the quantity needed to get the high you want.
I’m 33, I’ve been smoking for around 10 years. I smoke less because now I have access to better quality weed and more responsibilities. I’ve been trying to cut out some more, to be honest.