It’s a well debunked meme, see this thread https://twitter.com/danalarsen/status/1167941723969900544
Even in just the last 20 years(when we have much better data) there has been a large increase in potency.
Reminds of how there’s always that one person in any group who says something like:
“You reckon that’s good? You should try my cousins shit”, or some variant.
Or how every 25 / 30 / 35 / 40 45 / 50 / 55 / 60 year old / dead drug users will say “it’s not like it was back in my day”.