This is what they did with Between the Lions as well... sometimes putting the same episode 2 times a week. They ordered fewer and fewer episodes, and it led to it's intitial cancelization. There are new episodes now, but still, not that many.
I just have to say, I really wish that PBS would stop putting stock into new shows (unless they are quality) and expired fad type shows and put more into their stand bys like Arthur, Reading Rainbow (which doesn't even air in my market anymore) and Sesame Street. I mean, Tellitubbies, Booh Bah and Jay Jay the Jet Plane? I mean, those are more toy commercials than anything even remotely educational. Of course, it took Mr. Rogers's passing to have my market paly it on a regular basis again.