Time codes inside of analog terrestrial NTSC sounds really easy and obvious.
Given that nobody did it, it would appear that even though legally people like Mr. Rogers were making the case for time-shift programming, the industry must have assumed it was a minor use case.
The main reason I mentioned it is that I know I've seen various implementations--they're just not widely adopted. I guess nobody has the business interest to make it all work?
https://en.wikipedia.org/wiki/Radio_Data_System (FM radio) I figured this had an implementation considering text has been around for years. Amazingly, I don't think I've ever seen a car stereo use it to set the time!
Given that nobody did it, it would appear that even though legally people like Mr. Rogers were making the case for time-shift programming, the industry must have assumed it was a minor use case.