The same thing was true for cigarettes - even before all of the major studies came out lots of people were able to put together the obvious connection between smoking and lung problems.
Indeed, as is evidenced by the many comments in this very post claiming the study is bullshit or there's no proof of causality, or whatever else they can come up with.
Now that it's legal peoples' objectives have shifted and it's now ok to talk about it. It's a literal example of the stupidity in human psychology.
People don't use logic to make conclusions about the world, they use logic to justify their conclusions so they can fulfill their objectives.
Very hard to find a person who does cannabis on a daily basis and is also fully on board with the fact that cannabis causes cognitive decline.
I think it's important to point out that marijuana is certainly less dangerous than alcohol and cigarettes. But it's weird how people try to argue that there shouldn't be any sort of moderation when it comes to weed. Like, even alcoholics won't argue that they shouldn't be drunk all of the time.
(See Shulgin “The Nature of Drugs” pg 132)
And “constant” would be a better word than “permanent”, as certainly it should go away after some weeks of abstinence.
There's merit in the idea that stupidity correlates with success. Anecdotally you see the correlation among academia and celebrities. Celebrities are richer and happier then academics who are poorer but smarter. Therefore doing something that contributes to your stupidity could possibly increase your success and happiness.
What anecdotally makes you think that cognitive decline contributed individually to your success? I'm curious.
I too value my happiness and wealth over my intelligence, and I would gladly take a stupid pill if such a pill made the trade off between the two attributes.
There is also the argument of whether usage reduction is the objective goal though.