4th is still not a disaster, unless you are using a different definition for the word disaster. The world is not measured in absolutes. They were not as good as they should have been, they did worse then before, but 4th is far from a disaster.
Saying "We've dealt with that before as well" is glossing over a debate that was never, and won't be, settled.
They could have done better yes, but calling 4th a disaster when there can be only one winner, is dealing in absolutes.
Stable as their technical side has been, they have always kind of sucked as a group. The Brawn was the best car of 3, as it's hard to count any teams that had no DDD at the beginning of the year. Th 2005 BAR was quick and did well, but the team admitted that they never fully understood the cars success.
2006 - Jenson got a win, and did well in the last half of the year. Best scoring car for the last 6 races or something. Then the lost they plot for 2 solid years. 2007 and 2008 were utter jokes. Couldn't even have a car that braked stable, let alone turn a lap at all quick. They never looked good at all.
The team has a history of peaks and valley's with nothing in between, and based on that, 4th is not as disastrous as you seem to want to convince everyone of.
Calamity? Hiccup? Sure. Disaster? We'll see next season. If they can take what they have learned in the last half of the year, and apply it next year, at least this 'disaster' won't be for naught.