Lots of little reasons probably. Didn't Opera have those built-in toolbar banner advertisements for a long time? That probably didn't help. I agree the naming has always been a problem. Not that Firefox, Chrome or Safari are more descriptive names but they at least do not associate themselves with an art form that is generally considered to be lame or elitist. (not sure I agree but that's the perception in the US at least) Then again, to this day, a lot of people seem to think it's actually pronounced Oprah which is probably equally confusing but less negative to most people.