I should like to add that, once you leave the "main" areas of Manchester (city centre, near the universities...), it is more difficult to find a bus and there is a little or no competition. So, if you have a Magic Bus pass because it's cheaper to get to work and around the city centre, you are out of luck if you want to head to Urmston, because only Stagecoach goes there.
That article is interesting. I'm not sure how effective I think the "competition" is here.