imhomerjay, you must be a lawyer; you know
how to destroy an argument

. Actually, the
business about "disposable income" is an argument
television and radio stations with schedules geared
to the over-50 crowd (like some CBS affiliates I know)
love to make to attract ad business (I know, I once worked
for a radio station that played mostly big-band music and
that was our standard presentation to potential advertisers).
The problem is, I don't see too many potential advertisers
buying into this--literally or figuratively--if my experience
is any indication.
I'm sure the networks will target the 18-49 audience for the
indefinite future, and as I said, CBS has managed to attract
younger viewers with "CSI" and some of its reality shows
(but not its game shows like "Million Dollar Password").
The subject that I believe started this thread was the early-
'70s overhaul of the CBS schedule: the purge of the rural
shows and the introduction of shows like "All In The Family"
and "M*A*S*H" that were geared to a young, citified audience.
CBS felt it had to be done; NBC had come within a whisker of
winning the 1969-70 season, and ABC--once it shed three hours
in January 1971--also saw its ratings pick up. And Bill Paley,
persuaded it was the right thing to do, let Bob Wood and Fred
Silverman have at it. That's it. And it changed the face of television
for better or worse, depending on your point of view, since ABC and
NBC also dropped their older/rural-based shows.
Bottom line: I don't think CBS "blew it" but rather bought themselves
four or five more years at number one--until ABC outprogrammed them
with even younger, more urban-oriented shows.