the benefit of a retooling of the MBP would probably mean they have to change just to keep up.
Adding Blu-Ray drives etc. would mean the inclusion of a 1080 res screen at least, otherwise it would look stupid on a spec sheet and also be outclassed even more by cheaper Windows laptops with higher res screens than the MBP already is.
So even though they are ignoring the issue market forces may force them to better panels whether they like it or not.
The strange thing is that I don't get the impression that Apple is using particularly cheap displays. If you go to each manufacturer's site, these are not the low-end displays. So perhaps it's the LCD manufacturers we have to blame for not producing better quality displays? Sony seems to be able to produce really nice LCDs, but I've also seen some that are terrible with bad light-bleeding and uneven backlight so it varies there too.