This assumes they had a plot or purpose to stray from to begin with.

Between the non-nonsensical plot twists, and occasionally running with ideas that coincidentally cropped up in fan forums only the year before, it was pretty clear the writers barely knew more than the audience. Then it came time to end the series, but since they didn’t have a long-range plan, it was clumsy, didn’t resolve all the loose ends, and was generally kind of bad. So they soft-rebooted it for one more season, whose ending was even worse.