I do recall NBC aired their soaps at the right time in the 80's, 90s, and 2000s (when they had more then one soap) same as with ABC (Ryan's Hope always aired at 12/11 when it was moved to that time slot, same as Loving/The City/Port Charles at 12:30/11:30).
CBS moved Guiding Light from 3/2 to 10/9 in late 1997 and kept it there for a few years, then briefly moved it back to 3/2.. then the network claimed that the ratings were higher at 10/9 then at 3/2 so it moved back there till the show ended in 2009.
When I went to college in 1998/1999.. Sunset Beach didn't air during the day, it was aired on two different NBC affiliates in central Illinois, at either 1 or 2 in the morning, but when i was home on break, the show aired at 3/2. One aired that days episode, and the other aired the previous days episode. Guiding light aired one station at 2 PM and on another station at 3 PM.. same episode. Passions was aired at the right time in both the Chicago area and also in central Illinois (when I was in college).
I think affiliates helped kill a lot of soaps (i.e. Edge of Night, Search for Tomorrow, Loving, Port Charles, The Doctors, Ryan's Hope, Sunset Beach, Generations, etc).