Sadly this is no longer always the case with the advent of ATSC 1.0 and sub-channels.
An OTA TV license grants you 20Mbits of bandwidth in your market. The license holder is free to divide this bandwidth amongst however many sub-channels they desire.
In the last 7-8 years, the license holders (including CBS/NBC/et al) have continuously reduced their bitrates on their primary feeds in order to stuff as many sub-channels in their slice as possible.
Some of the majors in NYC (I’m looking at you ABC) resemble a RealVideo stream from 2002 more than a high-definition video from this decade.