Fox have always tried to act like the big shot and they believe that wielding the axe demonstrates that they are the corporation with the power to do as they please. What they don't realise is that other networks have much the same thing, but they would cancel poor shows.
Fox is owned by News Corporation - the plaything of Australian Megalomaniac Rupert Murdoch. This company runs the Sun and News of the World newspapers here in the UK and their management is much the same - get someone controversial and funny to run a column while they are this week's next best thing, then drop them straight away, as soon as they go a little cool. Their political view even shifts from election to election, picking the party that looks likely to win and throwing their lot in with them, faster than you can say "fill your boots"
I know that Futurama was one of the lucky few that managed to make a successful comeback (as a fan, I'd certainly say that it's a plus), but then so did Family Guy, on the back of DVD sales. What I would say in mitigation is that Fox isn't the only party guilty of cancelling a show before it's time, thinking along the lines of Farscape as an obvious example, but Fox has been rather more guilty of messing with the schedules and complaining that people don't then watch the shows.
Perhaps if Fox is going to be a bit petty about this, they should consider shorter seasons of shows and tweak the whole running order after 12 episodes, when new stuff comes into play? In the UK, our seasons are 6 episodes long and that is plenty of time to get through one decent sitcom - Blackadder gave us a different take on 4 separate time periods in 4 seasons of 6 episodes each. That's under 3 hours for a brief, but messed up history.
Then there's the flip side of the argument. The Simpsons. I own about the first 8 seasons on DVD and I've never had it in me to head to the shops and buy season 9 onwards. I bought the movie on DVD, but that was different, as I genuinely laughed at some of that plot... for a while. Sometimes, things do go on for too long, but the people behind it can't see that, as they're making money out of it. I'm still not sure what Groening was thinking with "I'd like a Simpsons Episode for every day of the year" Are you seriously going to sit through one episode a day? October will be almost entirely Treehouse of Horror and December will be a loop of Xmas specials. Have you really thought this through, Matt? The only reason you won't is because you've been paid for doing something that you teacher told you was bad back at school and you've become very wealthy off the back of News Corp. Well done.
Far be it for me to single out one story that started so brightly, only to be spread so thin over later seasons. There are other successful series that should also face the axe, but haven't done so, for commercial reasons, or even out of spite. These things happen and we just hope that by saving Futurama, we haven't doomed it to become the 31st Century Equivalent of the Simpsons.