A week ago, as the world knows, Germany scored seven goals against Brazil in the World Cup. In AFL football on the weekends either side of that match, there were nine instances of teams scoring seven or fewer goals. Another team scored eight goals - and won.

The soccer result was a historical aberration. The AFL scores were not. Since 2000, the average AFL score has shrunk continuously, from more than 15 goals per team per game to barely 12.5 now. This is despite constant improvement in conditions at all grounds, and from 2001 the utility of a ground, now called Etihad Stadium, where conditions don't matter at all.

This year, the paucity is especially marked. Only Hawthorn and Port Adelaide are averaging more than 100 points a game. The bottom three teams - Melbourne, Brisbane and St Kilda - are all averaging fewer than 65 points. The Demons, Roos-ian goodwill notwithstanding - are scoring almost a goal a game less than last year and nearly two goals a game less than in 2012.

AFL operations manager Mark Evans says there are nuances within those numbers. Scoring has become sparser this year, he says, but anecdotally, the top teams are attacking more. Further, the margin in matches between top eight and bottom eight teams has narrowed, a pleasing development.

Nonetheless, it makes for an austere comparison with, say, the Malcolm Blight era at Geelong. In 1992, the Cats averaged nearly 140 points a game. Wooden spooner Sydney averaged more than 90. Blight's philosophy was that football should be fun and he could think of no more satisfying football fun than kicking goals. However many the opposition kicked, Geelong would kick more.

Robert Walls, who coached good teams and bad, advocated the kicking of goals, because in the dog days, they at least gave fans and players something to cherish. As recently as five years ago, Matthew Knights' plan at Essendon was to give the Bombers a feel for the licentious thrill of attack before teaching them the more prosaic business of defence.

But the game's mindset had long since changed. Somewhere along the way, goalkicking became a responsibility rather than a joy. Geelong under Blight never did win the premiership, though he would win two with Adelaide and a more cautious approach. Knights was practically run out of Windy Hill. In 2005, Sydney kicked fewer points per game than in any of the three successive wooden spoon years 1992-94 - and won the premiership. Its coach was Roos.

It was modern football in apotheosis. When David Parkin became coach of Carlton in 1981, he knew the Blues were the best attacking team in the competition. All he had to do, he said, was instil a little defence mesh, and they immediately won two premierships. Since, with rare exceptions, the best defensive team of the year has won the premiership.

This is true of most of what Parkin calls "invasion" sports. Parkin, still crucially involved as a mentor and educator of coaches, lucidly explains why it is truer than ever in AFL. It is not simply the all-ground press than has become so fashionable. It is about what happens when the ball changes hands.

When a team loses the ball, Parkin says, players are well drilled in what they should do next. It is comparatively easy to teach. Moreover, coaches pick players to suit. A player with no defensive game is unlikely to get a regular start. And, Parkin says, the era of three tall but immobile forwards already is over. Forwards have to be able to roam to the half-back line, and back again.

When a team gains the ball, Parkin says, they are also habituated in what to do next. But it is significantly harder for players to learn, and coaches to teach, because it depends on retaining possession. A turnover at any moment can wrong-foot an entire team and is immediately punished. Any fan of any team can think of half a dozen instances from last weekend alone. Consequently, coaches more than ever, play safety first.

Cross-pollinating conversations with coaches from others sports - basketball's Brian Goorjian, hockey's Ric Charlesworth, soccer's Ernie Merrick- affirm this truth to be universal. After THAT World Cup semi-final, the focus was as much on what Brazil got wrong as Germany did right. Even to untrained eyes, it was clear Brazil's defence collapsed. It won't like that again.

Evans says it is not possible to substantiate a link between decline in scoring and decline in crowds in AFL. Scoring has been atrophying for years, crowds only latterly. Nonetheless, he is watching closely.

Low-scoring games can be entertaining as long as they are close. And a high-scoring game can become merely a clinical test of accuracy. Received wisdom, Parkin says, is that 10-15 goals per team per game makes for an ideal contest, sustaining hope for both teams. More, and it can become a shoot-out. Less, and football becomes gruelling for players and fans alike.

Here, the AFL must watch the canary in the coalmine. Ross Lyon, from the Roos line, is the anti-Blight. His St Kilda 2009-10 grand final teams averaged less than 94 points a game. Fremantle under him is averaging a little more than 92 points a game and is well-placed to reach its second successive grand final. However few goals his teams kick, he seems to say, the opposition will kick fewer. It nearly worked for Argentina.