Probably because if you had an old set and were watching on Ch2 but your neighbor was watching the same thing on Ch1 on a new set, that could have been a bit confusing at the dawn of television.

Or, watch ABC news on Ch2 on old sets, but Ch1 on new sets...., wait, do I have an old set or a new set?

I would assume they didn't renumber because TV was becoming popular at this point and it would be a hassle.

you tl;dr people are doing the lord's work. thank you

So instead of reading. --> fast paced audio.

I can read faster than any human can speak intelligibly. Also, it's much easier to skip ahead with text.