I”m living proof that your speculation is false.
Heavy user for over 31 years. I finally had to quit a few years back to insure I wouldn’t lose my very good and very technical job. I’ve always had a highly technical job that has been very demanding over the last 3+ decades and I’ve both excelled and been rewarded over those decades for my efforts, dependability and professionalism.
Not all people are slackers, and I’ve known many who are heavy users who are quite intelligent and motivated.
It is not speculation, it is observation and experience.
There are people who smoke who have successful lives if they have the self-discipline to not let it interfere with their work and their family. I said that.
Most people who start using regularly in their teens and are heavy users for years have low level jobs and do little but hang out, get high, go to the bar and things like that.