Bah, blaming Vince is ridiculous. Drug abuse was ingrained in the culture of the wrestling from a grassroots level. You think coming through the territories these guys were all clean? Nope, not happening. The only way to get booked was to look larger than life. Ain't no Daniel Bryans or CM Punks back then, they for the most part were jacked to shit, spectacle over wrestling talent. You think some random small time Tennessee promoter is gonna be asking for drug tests and not hiring a known draw because of morals? Nope. Not happening.
Not only that, they were broke as shit. Stone Cold lived on potatoes for months coming through the old system. Knowing what we know of protein and building clean nowadays, how you think Stone Cold had a nice body eating nothing but simple carbs? Yeah, exactly. And that wasn't because WWE Forced him or whatever, it's what he had to do to get ahead in the most cut throat of businesses. 99.9% of these guys didn't start in WWE, they just brought their baggage with them. It was bad back in the days, but things have definitely changed, and for the better.
But to blame an entire industry's failings on one man just because he is the most prominent is stupid. Blame the industry, not the man that has built himself as the face of it.