Personal anecdotes and bias. I’ve never met anyone successful who regularly consumes drugs as serious as cocaine. At worst it’s marijuana, with minor experimentation with harder substances in college or on special occasions.
"Regularly" is doing a lot of work here. Plenty of rich and successful people dabble in drugs. People with any level of wealth who can function normally in society while habitually and regularly using any substance are pretty obviously much less likely to develop a habit in the first place.
Not habitual and not anything harder than marijuana no.
I don’t believe that I have little life experience, I live in a wealthy part of the United States and my circle’s median income is in the 300s, so I think I have a pretty solid impression of the type of habits successful people engage in and don’t engage in