It's pirated because it was [too] successful and became the de facto industry standard - but if it hadn't done so, it would not have stopped tacky stuff - people would just use other graphics apps instead.
In fact, initially, most non-professionals probably were using other stuff instead, because pirating was much more effort before the Internet took off.
Wait... "when Photoshop 1.0 first came out" ...you were probably still at nursery, playing with fisher price or tomy things that made animal sounds when you pressed the buttons. :P
Bah.
EDITED: 16 Mar 2011 16:05 by BOUGHTONP