If you believe the problems are hugely widespread and very common, and the result of some inherent design defect, then no. It would be cheaper for Apple to fix the design problem. If you believe that the issues are less common, the result of normal defects from the manufacturing process, and far, far overblown in these forums, then, yes, it is actually cheaper for them to do that.
it seems to always come down to wether people notice a problem or not... i guess i'm just convinced that the majority will not notice (or care about) their subtle screen gradients, uneven backlighting and bleed-out... especially if they're coming from a $600 PC as a switcher and are not aware that previous iMacs never had this problem... apple is betting (undoubtedly correctly) that the amount of returns will not affect their profits, especially since they're started using cheaper flawed displays from LG-Phillips.
so i think the problem is apple's overzealous business sense.