I like the comment that the Tories have realised that already.
"While we do not have the benefit of hindsight, 2010 feels a lot like 1992. Most people are fed up with the government but unconvinced by the opposition. The ruling party has become too comfortable with power and often seems bereft of purpose. The prime minister is at best uninspiring, more often dismal. Most importantly, the economic outlook is unpromising - and there is a growing chance that a run on the pound will wreak havoc with the recovery and the government's plans. Even if catastrophe is avoided, running Britain in an age of austerity will be a thankless task, especially for politicians who believe in active government."
I've been thinking this exact same thing for a while, so it's nice to know that I'm so far ahead of even radical thinking at the Guardian (job please).
Second-guessing history is a dangerous ploy at the best of times, but I think there is some water in what the author's going on about.
One other factor I'd like to throw in is that if the Cameron project fails it's very likely the Tories would turn to their right wing for their next leader, who after 18 years of Labour (mismanagement) rule could probably win if certifiably insane (maybe bring Maggie back).
So it's possible that Labour winning under Gordy will mean an ingrained hatred of Labour among voters with them resenting every minute of the 5 year term, then the Tory right getting to power within the party and winning an election it's impossible for them to loose.
On balance I'm glad of the range of possibilities the author touches on, but I'd agree with the general premise. British electoral history shows that few are the government parties that go on and on and on. In the 20th century the Tories allowed the others to keep the seat warm for a spell here and there but ruled overall. Labour's, and the country's, best hope for the future would be a similar thing with Labour as the ingrained party of rule, but with the odd other party taking turns in the high chair before reality kicks in again and the big boys come to clean up the mess.
I would prefer that the Tories never won power again, but they will, and this year may be Labour's best chance to limit the damage they will do