I'd be happy with 10 or 13 if there were spinoffs - especially with crossovers. Thinking the arrowverse here -- how many shows are there in that? Arrow, Flash, Legends, Supergirl, all with 20-odd episodes. That's a lot of TV each year, and that's good. I was too young for the first dark age of trek, growing up during the golden age - TNG, DS9, Voyager. It was just accepted that you got 40+ new episodes a year. Enterprise was a gradual reduction to "wean" us off, and in the last 11 years we've had 3 films, 2 of which were actually good.
There's no reason an arc has to last a whole season. There's no reason you can only have 1 season each year. However the demands on the cast and crew do impact on the quality. You can help somewhat with the crew, by having larger teams, but the cast filming 26 demanding episodes per year, especially if all the cast are in all the episodes, is hard work.
I could see having 3 or 4 shows with crossovers each with a dozen episodes.
There's no reason an arc has to last a whole season. There's no reason you can only have 1 season each year. However the demands on the cast and crew do impact on the quality. You can help somewhat with the crew, by having larger teams, but the cast filming 26 demanding episodes per year, especially if all the cast are in all the episodes, is hard work.
I could see having 3 or 4 shows with crossovers each with a dozen episodes.
