Without modern computers "Greatest Common Denominator" was generally how networks determined which programs were aired - going back to radio days. Star Trek (Classic) was somewhat of anomaly as it consistently brought in lower ratings but had a higher than normal number of highly...
Unless things have changed since I worked for an NBC affiliate, most local stations count on the money the network pays them for running their programming (with their commercials). This could be a cost-cutting measure in that regard, but as I recall from skool the affilation agreements state the...