Plese forgive me if this isnt 100% accurate, as Im recalling stuff from memory here....
A couple of posters had asked what happened to the show and why it was only given one season. Expense was certainly part of that, but the show also got pre-empted a fair bit and didnt have a fantasic slot in the schedule.
At the time, Fox had another major sci fi hit on their hands that you'll most likely have heard of: The X Files. Morgan and Wong (the S:AAB creators had been writing for that show and were responsible for some of the major stories and the way the show developed. When they jumped ship and started up S:AAB, Chris Carter (daddy of the x-files) wasnt best pleased, and by all accounts managed to pull in some favours from Fox and have the show.....disrespected.
Chris Carter was a believer of his own hype. He seemed to believe that human conflict with aliens would only happen the way it was depicted on X-Files. (he also reportedly hated Indepndence Day for the same reason.)
Well that's just ridiculous. There are *much* better reasons to dislike Independence Day