Well the same could be said of most forms of art which were often created as a reaction to established order only to become the new established order. See: rock, rap, jeans, snickers, German language opera, abstract modern art.
Grafitti is beautiful vandalism. Paradoxical, controversial, illigal yet defensible, vexing and captivating at the same time. Under the protection of the law, only half of these remain, leaving grafitti with the artistic content of the common tattoo. Illigal, controversial and vexing now replaced with vulgar, crass and stupefying.
(not to put down tattoos as an artistic medium, i'm just saying nobody's impressed with your sick sleeve, George)