That would be all fine if there were plenty of examples where it went the other way. But it doesn't - the SH sides simply seem to get the job done against NH sides when push comes to shove, and ultimately you have to accept that isn't due to good fortune, but because they are better.
Historically that's been the case, at the moment I don't there's much in it, and arguably there's more breadth of good play in the Northern Hemisphere with a spread of abilities between Ireland/France down to Italy, whereas there's South Africa/New Zealand and then a gap down to Australia and Argentina. The test is going to be are there still going to be competitive northern hemisphere sides in three, four, five, ten years time. We expect this level from the Southern Hemisphere - Australia's below par performance is as much of an aberration as France and Ireland being competitive, historically speaking.
And don't forget that SA played 10 mins with 14 players and NZ played 20 mins with 14 players and they still both won.
New Zealand's card, though, were for professional fouls in attempting to stop try-scoring opportunities - some could argue it's that cynical edge that gives them an advantage, but I can't be confident that one of the more shrewd Ireland players wouldn't have taken the same risk. At that level they practice playing with a man down, knowing that it's a risk of the game. Ireland got a penalty try for the second infringement, and turned their numerical advantage in the first into a try.
France's inability to maximise their numerical benefit is perhaps a little more telling - as you suggest, the Northern Hemisphere sides are not used to being favourites in these pinch matches, and haven't developed the mentality to step it up a notch in those circumstances, to really punish when it's called for.
They won't be for long though will they - if they are really the top two in the world you'd expect them to be competing in the final rather than being dumped out at the quarter final stage.
I don't think it's as clear-cut as that - you'd expect them to win four or five out of six - what they need is to make sure that one of those is at the sharp end, and I suspect that's a combination of mentality and luck - the luck you can't control, but the mentality will come from playing at the sharp end more consistently.
I'm not convinced that the ranking works well with comparing SH with NH, simply because the only time they actually play each other in properly competitive fixtures is once every four years at the world cup.
I don't think you can watch an All Blacks game - any All Blacks game - and suggest that they don't give everything every time they pull on that shirt. Part of what makes them the legends they are is that you can't give them an inch, ever. South Africa breeds rugby players that, individually, are always physical, aggressive, domineering, it's part and parcel of the fabric of their game - that doesn't get let go for 'lesser' matches. You could argue that northern and southern hemisphere sides don't play each other often enough, perhaps, but you I don't see that you can suggest that matches outside of the world cup are noticeably less competitive.
So the rankings are good at telling you which 6 nations sides are better than which other 6 nations sides, and which rugby championship sides are better than which other rugby championship sides, but not good at telling you whether NZ are better than Ireland. The exception are the rankings immediately after the world cup, which I think will see NZ and SA one and two, not Ireland and France.
South Africa have six ranking points to make up to catch Ireland, which I'm not sure is mathematically possible given the timeframe the rankings are taken over.
Agree on Australia - they are poor at the moment and finished bottom of the rugby championship, but it is hard to argue that Argentina are not as good as the mainstream 6 nations sides as they've just dumped one of those, Wales, out of the world cup.
In a hard-fought, close contest that only got away from Wales (who didn't play to their capabilities) when they had to chase the game at the end, and Wales are a distant fourth in the standards of the six nations right now. Argentina would not be out of place competing against the six nations teams (and, from the little I've seen of them, didn't play to their best either), but they would be in the lower half of it right now.
I think the problem is just as much at international level as club level. The four SH sides get to play each other every year in a competitive tournament, which inevitably will involve the best side in the world (as the SH pretty well always win the world cup). So they constantly have the opportunity of the best playing the best. The 6 nations is a second class tournament in comparison. Win the rugby championship and you'll be competitive for the world cup, win the 6 nations ... well not so much.
It's a development problem - South Africa and New Zealand have a wealth of talent in each position, the northern hemisphere teams historically have always had maybe four or five world class players and a clutch of eager journeymen. It's only in recent years that northern hemisphere teams (led by France, but Ireland and England to a lesser extent) have regularly produced not just those world class players but a layer of depth behind it. South Africa and New Zealand have enough players of that capability in their leagues that the players need less coaching and tactical guidance, so when the 'second string' come in they don't suffer that drop in performance and (in England's case) they aren't a susceptible to questionable management practices.
O.