A sidenote:

These problems are further compounded by the image 'enhancement' features of modern TVs (often turned on by default).

I'm mainly thinking of the 'dynamic' contrast feature, which assumes that the darkest part of the picture at any given time is pure black (and the lightest part is pure white). This increases contrast at the sacrifice of a realistic image.

Another common issue is overblown colour settings.

Combined with poorly mastered DVDs as identified above, this gives a really second rate image, which I can only imagine people just get used to. It's a shame when most spend £100s on TVs and blu-ray players.