Speaking to the musical side of things as someone who has made a living as a musician for most of my adult life, there are a lot of failed/struggling musicians who abuse substances, but not many working, productive musicians doing so. Making music for a living in any capacity and any genre is hard work and takes a great deal of organized, focused thinking. When you meet musicians who are actually working, you’ll usually find them to usually be focused, hard-working, sober-minded people.
The substances that make people think they’re creative aren’t actually conducive to the real work of being a musician. If you want to write, it’s a bit of a numbers game. You write a lot of bad songs/partial songs until you write a few good ones. If you want to perform, you need hours of daily, focused practice for years. Musicians need time and a clear head to do their work. Substances only make that work harder. Some people sort of make it work, but it’s ultimately a drag on their productivity, no matter how much they lie to themselves otherwise.
The jazz cats who were all heroin addicts? They either got clean or died. The geniuses who got clean were still geniuses, just more productive. The dead ones were still dead. The same goes for any other genre.