I saw some vids on youtube explaining the value of image processing. You can calibrate much but you are always limited by the image processor and the image processor technology around it.
Sure, of course there is a difference between a cheap monitor and a high grade professional one, but my point is that most average users/players don't have these so it doesn't necessarily make that much of a difference for them.
Let's compare to recording music again.
If I record a music-track at a really high level of fidelity, let's say 192kHz, 24 bit, and then an average listener compare that to a recording at CD-quality (44.1kHz, 16 bit) my guess is that he or she will have a really hard time making out the difference, if at all. A recording engineer will probably hear the difference as long as the have a room with good acoustics and really good speakers and A/D converters, but since most listeners don't have that, well...
Also, the fact that the average human only picks up sound between 20-22.000 Hz makes a lot of that extra quality unnecessary since they can't hear it anyway. It might still be great to have while editing the audio during production though, just like RAW images from your camera are great when tuning the image, but not really friendly (due to size and other factors) when publishing the image.
You still want to make the "original copy" as good as possible though so, yes, good equipment still makes a difference. But whatever you are producing, if it's music or graphics, you still need to keep in mind that most of the subtle tweaks you make might not be picked up by the end-user anyway. They might be listening to your masterpiece through some crappy ear buds or watching your graphics on some old black and white tv set (ok, maybe a bit extreme, but you get my point
). So making sure your product looks/sounds good on both "bad" and "good" equipment is equally important.
