Once you hit about 30ish, your eyes will start to degrade.
I'm not talking about short sightedness/long sightedness and other lens related issues, the actual sensors just stop working, and your eyes lose resolution.
After having my eyes tested, and discovering the incredibly bad res my left eye seems to be picking up, I'm shocked to discover that it's significantly better than average for people my age. My right eye by comparison is amazing, apparently.
So, now much of the population is well above 30, and if you have a 1/2 decent upscaler (like the sony bravia engine X/W series TV's) the difference isn't so pronounced as the run-of-the-mill TV's out there, and really isn't that noticeable - especially if you didn't know the difference anyway.