Re: 2000 Malibu Road
It was supposed to be aired in the Spring of 1992 (hence Drew Barrymore's character's hope to land a pilot for the fall), but kept being pushed back. When CBS finally aired it - it became a huge smash hit! They did try to make new deals - but between the demands from the girls for a pay check rise, plus the fact that most of the sets had to be re-built, it never happened.
Re: CPW
The remaining episodes were originally going to be aired in March/April 1996 - both the Mariel/CPW eps! Obviously, someone decided against it and they got aired in the summer. No renewal unless they were smash hits. Which they weren't.