I'm also in my 40's and I haven't seen a reason for a TV to overscan in AGES. I only dealt with overscan when it was with old Analog signals like from an old VCR where timecode and close captioning data is on top most lines of the NTSC signal or when using a really old VGA to RCA adapter where you'd want the over scan to "stretch" your computer's desktop to fit the screen. I think your assessment is right, it's a hold over from before the Analog->Digital conversion and there hasn't been a big enough complaint to remove it.
