It is not just that Australia have lost two home Test matches to South Africa by wide margins.

It is the way they managed to include that joyous hint of farce into proceedings, most particularly with a fielding performance that had touches of pure England.

Imagine what jingoistic Australian cricket writers — is that a tautology? — would have said had an English side, toiling against a rampant Australia, allowed a No 10 chancing his arm to score 76; had they conceded in the course of a ninth-wicket stand a five with the help of four overthrows and another five by allowing the ball to strike a resting helmet, and had they dropped an infield skyer without the man even touching the ball. Wonderful stuff: it was hard to say whether Mike Hussey’s effort was more reminiscent of Corporal Jones from Dad’s Army — don’t panic! — or Colonel Blink, “The Short-Sighted Gink” from The Beezer. The one thing it didn’t remind you of was the Australian cricket team — it’s on YouTube, don’t miss it.

But it was not England in disguise. It was one more unmistakable symptom of the decline and fall of the Australian Empire. It’s the same country as before, it has the same academy system, the same famously exacting grade cricket, the same climate, the same culture — but all at once, Australia have gone from unbeatable to vulnerable.

When a real empire declines and falls, most historians look for large reasons, for sweeping unstoppable trends and for subtle points at which, when seen right, it is clear that things changed for ever. But sporting empires are less elusive.

England have spent the past decade and a half trying to do everything Australia did, employing real Australians whenever possible. Australia, while doing the same Australian things and with no shortage of Australians to call on, have gone from what might have been the finest team who ever played the game to an outfit who are there for the taking by any opposition who are good enough.

Australia have not slumped because the template is faulty, or because the system has failed. Australia have failed because two of the finest cricketers that ever drew breath have retired. The problem is not about systems, it is about people. It is about life. The problem is that extreme talent is very, very rare — in cricket, in any sport, in any walk of life.

Australia have for years had a considerable number of very fine players. But in Glenn McGrath and Shane Warne they had the difference between very good indeed and absolutely remarkable. That’s why the decline began with their retirement. For that matter, the turning point of the Ashes series of 2005 came when McGrath turned his ankle on a stray cricket ball while sodding about playing rugby before the second Test: for want of a man to do the tidying up, the series was lost.

That’s what happens. Time after time, in sport after sport, when empires decline and fall, it generally comes down not to historic and economic trends, but to the loss of exceptional individuals.

It is also suggested that in team sports, truly exceptional players make all the other players perform better. This is not just the concept of moral example and inspirational powers, although these things should not be underestimated. It is also because genuinely remarkable players create the time and space in which others can also excel.

Without McGrath and Warne to take regular five-fers, Australians are spending a great deal longer in the field. This makes fielding increasingly difficult, as Hussey will be the first to tell you — it also makes batting afterwards a far more challenging task. That’s why you so often get a batting collapse after a team have spent five sessions chasing leather.

Every great team must look not only for excellence but for succession. The ultimate achievement in team sport is to create a dynasty. It seemed during the 1980s that West Indies had managed this, as Viv Richards succeeded Clive Lloyd as captain, as Andy Roberts was succeeded by Malcolm Marshall and he by Curtly Ambrose as the main strike bowler; as one fine fast bowler seemed to follow another on the principle of the conveyer belt.