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 in a country with a fairly restrictive medical cannabis system. I can’t compare stuff from back in the 70s or whatever as I wasnt born yet lol. But I can compare the lowest THC strain I have against the highest. I have 12.5%, 15% and 21%. (For context I only vape and only microdose).
The lowest one can give the highest one a run for its money in terms of how much it hits from one inhalation. But it doesn’t last ovr many hits. The lowest might only be 2-3 hits from the bowl. Whereas the highest I can get easily double that before it becomes naff.
This for me means the stronger stuff is way better value for money.
The downside is that you don’t get as much terpenes - the lower strength will be a bowl a session. Whereas the higher strength, a bowl can last two or three sessions and I’m only getting the yummy terpene hits off that first session.