Maybe some here have, but I can say that I've never personally known any serious pothead who were successful in life or career. The ones I've known/know just sleepwalk through life. I saw an interview recently where one of the smokers who invented the term '420' and owns a legal pot business said he stopped smoking years ago because he found it hindered success and he saw that the heavy smokers he knew had life issues they were trying to numb. They had bad careers and relationships either as a result of smoking or vice versa.
Can't paint everything with a broad brush
I know people who would smoke their fair share of pot and still become successful.
Now if you are considering someone who smokes sevearl times of day, I agree - same can be said of someone who drinks a lot.
I went to Tedeschi - Trucks at Simsbury last summer and could not believe the number of folks in their 60s talking about their grandkids and their jobs before the concert and when the lights went out, out came the pot. My daughter who works at the Hartford saw at least a dozen high level officers and their spouses/significant others puffing away and trying to be clandestine about it - she was shocked.
I was at the Dead and Company show at MSG this past fall and there were 3 couples behind me - two of the guys worked at a major bank in the corporate funding area and the other guy owned an investment firm in midtown. Being in the banking field myself, I struck up conversations with them. These guys and their spouses are good for $500K per year - easy. Again, when the lights went out the puffing among the 6 was continual and if I hadn't given it up years ago, i would have partaken - the invitation was there.
I attend many concerts a year and see these sights at virtually every one.