(Reminder: This storyline IS canon. It's exact place in time, however, is presently unknown.)
My basic motivation for Rich's development was that I wanted to keep him around without him being completely insufferable. I think it would have been an acceptable story for Rich and Larry to grow apart, but it's also not a story I had any interest in telling.
It would pretty much have been the "Rich is acting roughly how you'd expect him to, and Larry is gradually having enough of it" show.
I didn't really want to watch that.