I have a Sony Solid State (pre-Trinitron) from 1972 that still works fine. I actually played a game of Madden on it last year, hooking my GameCube up via RF modulation. It's a 10" monochrome display unit that overall is about as large a Mac LC with a 12" monitor on top of it.

I think the older electronics were better designed and I do believe the TVs were designed with constant use in mind. When Macs first came out in 1984 they were more of a novelty item, not something that would be running from 8AM until 5PM.