Happens more often than you think.
Nurse Betty, another example, I think that it could be the way that they release titles in the cinema. Very much of the release dates in the UK doesn`t really matter what title the title streets, in America, they have prepared it years in advanced, film companies shift schedules so certain titles don`t clash. For example, July the 14th in America will be dominated by the popcorn fare. During this weekend, you will not get much else released, studios want to maximise profits and they need to pick dates specifically. In a way there are patterns all year round. There are usually very little of interest during Feb to early march, then comedies usually before the oscars. After the Oscars you will get a few intelligent films, easter will be dominated by family fare, April will see the smaller films released, with one or two biggies that want to be out of the Summer battle. this will press on until around June, then the battle commences, where there will be at least 2 films that share similarities, big brash no brainer attracting all the money regardless of critical mauling, several big budgetters that will flop, lets just say there`s a lot of marketting, alot of exposure, alot of releases, with very little amount of the independent releases occurring. It`s only until the end of arounf August before several films that missed the race arive, the second similarity film is released, a really dumb assed film gets $100 million, and the rom-coms or dramas are released. From then to November there are a slower number of films released, one or two comedies, something really unique and original, an epic, a few turkeys that go into number one stateside for a week. You get the teen films, slashers around here. It`s only around November to December that such films can survive, as the cinemas are inudated with festive family films and family comedies and more family things, let`s just say, it`s very Christmassy. So that time frame sees all the remainder of the independent distributed films are released (Nurse Betty here), slowly though, like the blockbusters, they need to allow each film to profit, these will be vying for the Oscars. In to January and you get the remainder of films that couldn`t be fit into the festive period (O`Brother where Art Thou), usually a few gems that will have seen small distribution at the end of the year, now with a more widespread release (The Thin Red Line was such film), these will also be trying to pitch towards the oscars.
This may be a bit to contrieved, but hope it helps in some way.
At the end of the day, I`m trying to say that it is about he distribution dates, such fares as O`Brother Where Art Thou aren`t major films, they will not make money, there is no demand, no publicity. In a way, these films, regardless of whether they may be the best film of the year do not need to be released until there are gaps to cover, or just to be released for the sake of it. (someone might aswell prove me wrong here)
