the whole "they'd be smart if they did this" argument always seems faulty to me. that's going by the assumption that quality equals profit - and, to a more myopic degree, that quality to you equals money [for them]
warner could put on the greatest watchmen retelling, evar, over a 12-episode HBO run, meet every message board critique they could encounter (mystically managing to stick exactly to the script of the comics, without actually sticking to the script of the comics). rave reviews does not guarantee a success.
they spent a brazillion dollars making and promoting "dark knight", and that worked in spades. why? maybe just cuz "batman" was in it. or maybe cuz it was friggin awesome. maybe a nice combo of the two. maybe it really was because they killed an actor to improve the reaction. who knows, lightning in a bottle.
but there have been equally expensive films (or projects), and equally well-made films (or projects), that have tanked. if memory serves, far moreso.