Romanticizing Aesthetics

It is cool to copy a worn out, low-class grunge look.  It is less cool to actually live the life that is associated with the look.  I.e. what is actually cool is the ability to dip into a persona, all the while maintaining the ability to pull out of it. What's cool is to act, to play with identity, not to be restricted to one identity.  I wonder why this is.