I think the lines have been blurred considerably in DFW
since I lived there; KTVT (licensed to Ft. Worth) has
replaced KDFW as the CBS station and has become quite
competitive in both cities. Likewise, in Norfolk WVEC isn't
hurt by the fact that in the 1980s they hired Jim Kincaid
from ABC (he's now retired) and the ratings began to move
up; WVEC's news also follows Oprah. WTKR, the market
leader when I lived there in the '60s, has been through a
lot of turmoil, especially in ownership changes.
But sometimes a network switch is to the good; I keep going
back to WTSP St. Petersburg, which is far stronger with CBS
than it ever was with ABC, but the Bay Area's demographics
tend to favor CBS.
I got to thinking: what markets, since ABC's ascendancy in
the '70s, still have the same ABC, CBS, and NBC affiliates
as then? New York, Los Angeles, and Chicago don't count)? Some I know of:
Little Rock
Colorado Springs
Hartford/New Haven
Washington, DC
Orlando
Ft. Myers/Naples
Tallahassee
Columbus, GA
Augusta, GA (technicality: WJBF acquired exclusive ABC
affiliation around 1977)
Boise
Ft. Wayne
Peoria
Topeka
Wichita
Lexington
Paducah/Cape Girardeau/Harrisburg
Des Moines
Cedar Rapids
Sioux City
Mason City/Rochester/Austin
Shreveport/Texarkana
Bangor
Portland, ME
Grand Rapids (somebody correct me on this)
Traverse City/Cadillac
Duluth
Jackson
Lincoln (I think)
Las Vegas
Reno
Albuquerque
Buffalo
Syracuse
Greenville/New Bern/Washington
Columbus
Youngstown
Oklahoma City
Tulsa
Portland
Eugene (I think)
Pittsburgh
Scranton/Wilkes-Barre
Erie
Greenville/Spartanburg/Asheville
Columbia, SC
Nashville (channel swap: ABC and PBS, Chs. 2 and 8)
Chattanooga
Bristol/Kingsport/Johnson City
Houston
San Antonio
Amarillo
Corpus Christi
Lubbock
Abilene/Sweetwater
Wichita Falls/Lawton
El Paso (there was an ABC/PBS channel swap
between 7 and 13)
Burlington/Plattsburgh
Norfolk
Richmond
Roanoke/Lynchburg
Yakima
Madison
LaCrosse/Eau Claire
Wausau/Rhinelander
Anchorage may also be one; Honolulu is not, since NBC
moved from KHON/2 to KHNL/13. I have also excluded
markets, such as Savannah and Jacksonville, where a
station switched, then went back to its original affiliation
(WSAV and WTLV, respectively, went from NBC to ABC
and back to NBC--Columbus, MS and Columbia, MO are two
more--Columbus from CBS to ABC and back; Columbia from
NBC to ABC and back, and KIRO Seattle went from CBS to
UPN and back).
Harrisburg, PA is also not in this list: Chs. 15 and 43 both
dropped CBS.