Radio3787 said:
I never understood why network programming wouldn't just solve the problem by making prime time
at 8 Eastern and Mountain / 7 Central and Pacific.
It would disrupt long-time viewing and sleeping habits. You don't want
cranky Nielsen families! ;D
Viewers in the Mountain zone have typically been, as in the midwest,
earlier to bed, earlier to rise. News at 11 PM and Jay/Dave at 11:35
would be too late. Not that the Mountain Time Zone has ever meant
anything to the networks, but this would make us "hate" New York
and the east coast even more.

It's bad enough that certain cable
companies
(cough...Cox...cough) have love affairs with left coast feeds
(Pacific plus one hour makes things even later).
As for the left coast, the biggest gripe there would be from the affils
who wouldn't want to lose the lucrative access hour (7-8 PM PT),
especially those with the
Jeopardy/Wheel Of Torture franchise. Some
PT affils have tried "early prime" (7-10) in the past but most have gone
back to 8-11. The SMF CBS (O&O) station still goes early, but I can't
recall any others still doing it--this of course takes them out of the
left coast feed and makes them delay prime themselves.