This is all so very interesting. Makes so much sense.
So.... I could see, and support mind you, going for the formats that these lonnnnng running shows have. e.g., all the
Law & Orders and
New Tricks has been going since 2003. L&O and NT use the long term system; not a big or systematic turnover but people come and go. Some leads stay for years and years, some stay for years, some a year or so, some shorter. Only once in a great while do they have 'surprise' exit or death, and for the show to continue being the same show nobody 'has' to stay forever. Some even leave and come back at a later date.
I definitely prefer the, what is it called, stand alone... no, it is episodic StarTrek. I would not enjoy the 'to be continued' and 'last week on Star Trek' or season ending cliff hangers.
If viewers could be factored in as shifting, and main lead characters hang around long enough to be beloved but also with natural shifting, and ship upgrades be natural over the years? I could get to really like this kind of StarTrek television show.

Anyway, that's the direction your 'Magic Bubble' discussion got me to look at. And now I'm rather excited about a StarTrek format like this.