And in the case of the US,what they have now is a generation of genuine athletes growing up with rugby as their chosen sport.
The distinction is critical. For decades, rugby in America filled a void for alternate sport-seekers at Ivy League universities or was something failed NFL wannabes fell into. Everyone used to talk about gridiron converts as the future of the sport but a lifetime in the anaerobic, structured American football world does not remotely prepare anyone for the aerobic, nuance-riven game of rugby.
The Americans' patience is going to pay off. By building a strong playing base they have a sustainable structure. In time, legions of skilled players will emerge into adulthood- players who grew up thinking, breathing and knowing only rugby.
There aren't many, if any, in the current US Eagles set-up who have been rugby for life and that will be the single biggest difference between the two sides at Soldier Field.
What will be fascinating is if the same fixture is played in 10 years' time. The gap between the two might not be so big by then. There's quiet confidence within American rugby circles that, by the 2019 World Cup, or possibly 2023, the Eagles will be able to consistently beat the weaker Tier One sides.
Longer-term followers of the international game will be sceptical. Since 1991 when they acquitted themselves surprisingly well at the World Cup, the Eagles have been branded a sleeping giant.
At the 2011 World Cup - and no doubt this week in Chicago - they didn't appear to be in any danger of waking. In 20 years, it's not obvious the Eagles have advanced much in terms of their overall skill and tactical development.
But that's poised to change, and not just because of the new generation that will soon emerge. The top end of the game is set to change, too.
Firstly, the inclusion of sevens in the Olympics is significant. The US is an Olympic nation and new funding is coming into the game. Rugby, through sevens, will benefit from greater investment, profile and numbers of good athletes equipped to pass, catch and tackle.
Secondly, there are murmurings of a professional, domestic competition on the cards. Various ideas are thought to have been explored but the one with most traction is inviting English Premiership sides to set up franchised off-shoots in the US and fill them with a mix of their own academy and development players and emerging local talent.
Thirdly, and perhaps most importantly, the IRB are inevitably going to be forced to move quickly and decisively after the World Cup to come up with a meaningful and sustainable fixture list for emerging Tier Two nations.
It simply won't be possible by the end of next year to pretend they are doing enough for emerging countries such as the US, Georgia, Samoa and Tonga. The World Cup, as it did in 2011, will highlight that the best Tier Two nations are loved for only six weeks in every four years.
The US, for example, are lucky to play six tests in any given year. It's not enough for them to build and develop game plans, skill-sets and continuity.
It hampers their ability to win sponsors, sell broadcast rights and grow the profile of the game.
"The All Blacks play 14 [tests]," says USA Rugby chairman Bob Latham. "England played a similar number last year, I think. If you look at next year-when there will be a World Cup-we won't play any tests in June and that is a problem. We will be trying to compete with Tier One nations at the World Cup and, yet, we only play a Tier One nation once a year and not in World Cup years."
Just as Argentina became the elephant in the room that could no longer be ignored after finishing third at the 2007 World Cup, so too will the emerging nations have their solution by 2016.
The US don't particularly mind what the international season looks like from 2016 as long as they gain access to better opposition and better financial returns. And in terms of putting pressure on the IRB, this week is huge. If the All Blacks - reigning world champions and biggest rugby brand on the globe - are prepared to play in Chicago, it's a powerful statement about the credibility of the US.
"They [All Blacks] are great ambassadors of the sport," says Latham. "The test will be a great opportunity for anyone [American] who has ever picked up a ball, or who has rugby in their soul, to celebrate and enjoy.
"I think a lot of people will see we are credible enough to host the world's best team and that the game will reveal the people who play this game have fantastic values."
