Some famous person was asked "Why do you sing?" answer, "Because I have to." Can't remember the friggin' name.

I've known people who are driven to perform just as a rat is driven to gnaw. They suffer terrible pain if they don't.

In the case of Hank Williams and others, they have to perform and they have to drive themselves beyond what any normal person can take, so it's booze and drugs to keep them on their feet.
It's like long haul truckers high on "goof balls" to over ride their need for sleep.