Fashion is fickle. What one, subcultured, unique group wore years ago is something every poser now has today. You could say that about nearly any trend - except Doc Martens.
People don't buy them on a whim. The heavy, clunky style rarely appeals to just anyone. And the interior is only tougher, often taking 3 months of savage blistering to break in.
And that's why when you see someone going about their day in a pair of Docs, it immediately tells you something about them.