It's strange that depending on the artform people have very different attitudes regarding how commercial things should be. It's generally accepted that for blockbuster films with blockbuster production values there needs to be a strong mainstream appeal - how else will you recoup the costs? But barely a day goes by in music where a band isn't accused of "selling out" and in certain artistic circles it seems that popularity is not just unworthy of pursuit but to be actively avoided.
Does it diminish the artistic value of a piece that it has been crafted for the majority? Is it dishonourable to want to make money off your art and to make a conscious effort to do so? Is it possible to achieve those ends without compromising on your artistic vision? Does art have a responsibility to challenge? Should an artist's main concern be to entertain himself or his audience?