The most phenomenal achievement of the All Blacks has been to maintain their primacy once the game went professional.

Conventional wisdom of the day went something like this: the All Blacks were, in terms of attitude and preparation, a professional team in an amateur era and once the game went fully professional, the rest of the world would quickly catch up.

"It was something I can distinctly remember talking about with the guys," said Justin Marshall, All Black halfback from 1995, the last year of amateurism, to 2005. "It was a genuine concern.

"Here we had this provincial championship that was the envy of the world, and we were diluting that to play Super 12, where the South Africans and Australians would be exposed to the skills and habits of our best players on a weekly basis."

"We thought the gap would close very quickly."

For a while it looked as though that prophecy might turn out to be true. Australia enjoyed a golden age during what we might call the John Eales era, and it took until 2011 for the All Blacks to win a World Cup in the professional era.

But the All Blacks test record has remained largely unimpeachable since 1996, despite more riches available in France and England in particular.

New Zealand rugby cannot compete on price with clubs in England, France, Ireland and Japan, but through strict eligibility clauses and clever harvesting of the All Black "legacy" they have managed to retain most of their best players and keep winning. Their record hit perfect status in 2013, with 14 tests and 14 wins.

In the amateur era, the All Blacks won 71.2 per cent of their tests, while drawing a surprisingly high 5.1 per cent of tests.

This is an outstanding record, obviously, but you could also argue that rugby meant more to the national psyche of New Zealand than any other team they encountered outside South Africa. That passion and unstinting dedication to the sport meant New Zealanders were more innovative and 'professional' than their opponents.

In 1995, rugby was undergoing seismic shifts. The World Cup in South Africa was a unifying, uplifting tournament and in Jonah Lomu rugby had its first truly global superstar.

Pay TV services, such as Sky, were aggressively pushing into new markets and sport was the common battleground.

Kerry Packer didn't have rugby and he wanted it, much like he wanted cricket in the late-70s. Ross Turnbull was sent out as Packer's envoy and he very formed a breakaway to match that of the original World Series Cricket. Popular legend would have it that the late Jock Hobbs managed to talk the All Blacks' two brightest stars - Josh Kronfeld and Jeff Wilson - into staying loyal to the then NZRFU and the proposed World Rugby Corporation folded in on itself from there.

Establishment-back rugby was instead sold to Rupert Murdoch and pals, turned professional and became what could be known as the test-match age. Tours, the likes of which made the All Blacks, Springboks and lions famous, were effectively over and instead hemispherical tournaments took precedence.

A tour to or from the Springboks was once an almost mystical - or in the case of 1981, hysterical - experience, New Zealand now found themselves in the Republic more times than they would ever care to wish.

South Africa is an interesting case in point. By far and away New Zealand's toughest 'amateur' opponent, the All Blacks' post-professional record against South Africa has improved.

Before 1996, New Zealand and South Africa met 42 times: the Boks won 21 of those tests with three drawn. They have played 48 times since 1996 with the All Blacks winning 34 times and no draws.

So the All Blacks have won 52 times in 90 tests - a very good record against our traditional arch-rivals and one that has only got better since rugby went professional.

In fact, it is indicative of New Zealand's professional record as a whole.

That is a win percentage of 83.1 per cent in the professional era, more than 12 points better than their amateur record. Even accounting for the fact that World Cups mean you face more minnows in the modern era than you did in the past, it is a stunning result.

As you can see by the final table below, the All Blacks professional pre-eminence has lifted the overall win percentage to a tick under 77 per cent.

The obvious question is, why? Why hasn't the advent of professionalism raised the bar uniformly among rugby's test-playing elite. Why hasn't New Zealand's inability to match the amount of money in bigger markets hurt them. We are not, it should be noted, in professional rugby's infancy any longer.

The answer is elusive, but there are some sound theories.

Money only gets you a stake at the table. It's what you do with it that counts. In other words, the English and French leagues might be awash with pounds and euros, but is that money actually helping the national side? It's just as likely to be lining the pockets of second-tier international players than assisting England or Les Bleus get better.

Second, professionalism does not take into account the intangibles.

To use a loose example: Scotland's players are just as professional as the All Blacks now in most respects. They train hard and have access to the latest sports science theories and practices. They should not, theoretically, be any more tired in the final 20 minutes of a test than the All Blacks.

They also have access to top quality coaching so, in those realms of rugby that remain technically driven and largely static - that is to say, the set pieces - they should be as strong and close to as proficient.

But you'd back the All Blacks to beat Scotland every time. Why? Because they have players that can win you games through a piece of brilliance; Scotland don't.

"It wasn't until I played overseas that I realised the true advantage New Zealand has," Marshall said. "It's our forwards: their ball skills, intelligence, speed at which they play and the way they read the game is miles ahead of anywhere else.

"Yes, South Africa are physical, but they still try to run over you. I look at somebody like Schalk Burger and it's really only in the past few years that he has tried to add ball-playing to his tremendous physical assets.

"England haven't caught up yet and probably won't for a while to come."

In terms of France and England, Marshall believes the promotion-relegation element of their top leagues work against the ideals of open, running rugby. As soon as a couple of games are lost, coaches go into their shells and revert to low-risk rugby, which stifles innovation and ball-playing.

"Speed, power, endurance - New Zealand forwards are probably no stronger here and might even be a little weaker, than some teams. We're just more skillful than the rest."