Which brings us back to Dan Carter and the calls for his head. We can only defend the critics' right to say it. But what utter bollocks ...
The debate is beginning already about whether Carter and the equally amazing Richie McCaw will be in the All Blacks' top XV, come the 2015 World Cup.
As the architects of the human race and the process of evolution have deigned not to equip us all with the ability to predict the future, any opinions on whether these two great All Blacks will make it are about as valuable as a soggy potato chip.
Cruden is a fine player but Carter critics should look back to the France test. Play the video and watch all the tackles he makes as the All Blacks are put under pressure. If I was an opposing coach, I would instruct my ball-runners to take route one to Cruden.
He's picked up his defence, no question, but he is still a small man, prone to being run over by the bus. When Cruden comes on after 52 minutes or so, his first act is to miss a pressure kick at goal. Carter tends to kick those as if he is pouring a cup of tea - a routine act made remarkable by an ice-cool demeanour that rarely sees him slopping it in the saucer.
He is a runner, too - that trademark surge and fend often taking him through the opposing line. Cruden is also effective here but his loopier style of running, with ball held in front with two hands, sometimes leads him down blind alleys. He does not yet quite have Carter's ability to connect the dots.
Carter also has one of the principal assets of the great - time. They have a little computer in their heads that the rest of us don't. This whirring mixture of grey matter and intuition allows them to capture a moment of great intensity and speed and freeze-frame it in an instant - allowing them to process the information, apply vision and pick the right response in a nano-second. Most of us, faced with the same pressure, would curl into the foetus position and pretend to be a grapefruit.
Cruden does not yet have this ability (excess time, not pretending to be a grapefruit ... ) though he could well develop it in the next two years. Greats can be made as well as born.
Finally, Carter has that immeasurably valuable asset - motivation. He isn't hanging on for the World Cup because he enjoys touring or because of a sense of entitlement that the No 10 jersey hanging on the peg in the dressing room is his.
None of his World Cups have gone to plan; he was a bit player in 2003 (at second five-eighths), criticised in 2007 for playing when injured and invalided out of things in 2011. He has not yet stamped that authority of the best first-five in the world - and possibly the best player in the world - on rugby's greatest prize. He has a World Cup winner's medal but, perhaps, not yet the satisfaction that should go with it.
The All Black coaches are harnessing this, protecting him by allowing his sabbaticals, resting a body increasingly prone to injury and cosseting that genius. They are also changing their views - and have said that first-five, like halfback, is a two-man job. That's why Carter was dragged off after 50 minutes for Cruden - it preserves one, propels the other. It's only sensible, even though some of us don't like to see Carter go off when he clearly has more to offer and needs time to settle into his game after an injury absence.
Just as it is possible to see McCaw at the 2015 World Cup as either a 6, 7 or 8 - or someone who can fill in at all three positions, courtesy of that amazing engine and technique - so Carter could, at a pinch, play at second five-eighths, his original All Black position, if needed. That's if Sonny Bill Williams is broken or has decided he wants to become a world champion ice skater and/or if Ma'a Nonu (who will then be 33) has headed overseas in a search to find someone who loves him.
No one can beat Time. But players like Carter have the ability to send it on a wild goose chase for a while. Frankly, if I was a 2015 All Black going to the World Cup, I'd want the unassuming bloke from Southbridge with me.