Overread
Searching for a flower
So what is the secret of the Soap Opera? I mean, those shows go on for years.
I think its a combination of aspects
1) Their audience has loyal followers, but at the same time a lot of people who filter in and out. The writing is such that you can pick them up and put them down fairly easily. Even if you might not get some of the long running stuff, there's enough short term to keep you interested if you're of the kind of person to like soap operas.
2) They are a good place for steadily retiring or actors between projects. Long term actors will remain, whilst many others will appear for a short story arc and then move on. So in part I think they give a repository of roles for actors to step into when they might otherwise find themselves out of work with the bigger, but short term drama series.
Much like how many actors might also do roles in theatre and the like between big TV productions.