Yeah, your basic point is correct. I just had to laugh at those numbers.
Heck, there were a number of households that didn't even have a TV back then.
But a lot of people watched the nightly news, and at best there were 3 choices: ABC, NBC and CBS. And for those of us who didn't live in a big metropolitan area we were lucky to get 2 of those when the weather was good. Because of channel availability, we usually watched Cronkite. Morrow must have been on a channel we didn't get. I'm familiar with name/fame, but I don't recall watching him.
Fern