How come some series in the 70's

[tvbdude]

are very short and it doesn't look like they even ended yet? take this series for example http://imchi.blogspot.com/2009/02/blog-post_11.html

there's another short series with liza wang and george lam called the couples that seems like it didn't end yet at the last episode.

is this normal for some series in the 1970's?

[Ken Cheng]

If it's a sitcom (and I think this series was) that has very little episode-to-episode continuity (like most American sitcoms), then perhaps it followed the Western TV model where the show just stops being produced when the ratings have fallen far enough...without specifically ending any storyline except for the most recent episode's.

That's rare for Asian TV, though.