We've had threads like these for years now.
Here's some hypotheses:
1. It was supposed to air on Fox. Fox is notorious for greenlighting shows it never intends to air, or suddenly changing it's mind based on the whims of a few key execs
2. Fox just got bought out by Disney and Disney probably doesn't give two shits about any of Fox's properties that aren't Simpsons
3. All the VAs have moved on to better things and airing the first season knowing how much of a hassle getting a second season going is probably on the financier's minds
in other words, the longer the hiatus goes on, the harder it is to get the show airing in the first place. Just think about that Star Wars Detour show that will never see the light of day.