Among fans the rumour that both Matt Groening and David X Cohen might want to step back from the show a bit in the future (besides the current hiatus thing going on) was rather common, so I thought I'd try to clear that up:
In a recent mail from David X Cohen (exec producer of Futurama) he explains that he still is very dedicated to the show. He just can't work on the show till midnight each day like he did in the past. He thinks Matt feels the same.
So no, they weren't backing out but getting back to a more normal work intensity.
PS: petition is at 72,000 signatures. Don't forget to (snail) mail!
PPS: The song at the end of Leela's Homeworld is "Pizzicato 5- Baby Love Child" and on their album "Made in USA"