well, keep it up, hope I won't disturb if I put a thought even give an answer to the question man .... so, Mainstream/UG ?
I think both have strong advantages, but I also think one can't exist without the other one. Simply, like Black/white. So, there will always be UG around, some guys playing a Demo, a little gig in a suburb, a band drunken on stage etc etc etc ...., but there will also always be skilled bands that go for worldwide tours, overloaded albums promo in glossy metal mag., ultra polished albums that just shine more than the CD in the player etc etc etc .... for now.