By Mark Orlovac
BBC Sport in Paris
Cusworth has worked with Argentina since 2001
Pumas rugby director Les Cusworth says the Celtic nations could learn from the structure of rugby in Argentina.
Cusworth believes staying amateur has benefited Argentina while countries like Wales and Scotland have struggled to establish a professional elite.
"Lots of amateur clubs have gone because of professionalism. To get an elite, you need a wide base," he said.
"We have a base other countries would die for and our future, while amateur, is a lot brighter than many nations."
Argentina have made the quarter-finals of the World Cup despite a lack of resources and preparation time while their top players ply their trade in Europe.
The strength and passion of the game in England, Scotland, Ireland and Wales is based in club rugby and we have dismantled all that with the professional game
Both Wales and Ireland failed to reach the knockout stages and Cusworth, a former England fly-half who has been with the Pumas since 2001, says Argentina's decision to remain amateur has been vindicated.
"I have changed my opinion significantly over the last two years," he said. "Especially if you look at the problems Welsh and Scottish rugby has gone through.
"The strength and passion of the game in England, Scotland, Ireland and Wales is based in club rugby and we have dismantled all that with the professional game.
"As soon as you bring in payments a lot of people stop working.
"I would go back to the club structure tomorrow and let the top players go abroad. Could you not have a couple of sides playing in the Magners League based at those clubs?
"If you have mediocre seasons for a couple of years, fine - but get the business structure organised first.
"We have 60,000 people playing rugby in Argentina and 82 clubs in the Buenos Aires province alone. There are 400 Argentine players playing rugby in Europe. If you take 400 top players out of the Home Nations, what would be left?
"The real reason we are all here is for kids to be playing the game. If we encourage them just to play for the provincial sides, you have 3% in the elite. What about the other 97%?"
Argentina have risen to fourth in the world rankings despite being without regular top-flight competition and have fought a lengthy campaign to be included in either the Six Nations or the Tri-Nations.
Scotland are the most improved team in the tournament
And Cusworth insists the prospect of inviting the Pumas into something like the Six Nations should not scare the established countries.
"Where is this game going, where do we want it to be in 30 years time?" he said. "Do we just want a Six Nations or a Tri-Nations? What a stagnant game we will have if that is the case.
"It would be better for us to be in the Six Nations. We could base ourselves in Brussels, Valencia, Madrid, wherever.
"If we are included it will benefit the incumbents. Let's get into the cosy club. The International Rugby Board have been very supportive about our case but they are not the stakeholders. The stakeholders are the Six Nations Committee."
The immediate focus for Argentina is Sunday's quarter-final clash with Scotland at the Stade de France.
The Pumas, who defeated hosts France and Ireland in the pool stages, are on the brink of reaching the semi-finals for the first time but Cusworth says his players are not feeling the pressure.
"This is a journey for them," he said. "Whatever the result is on Sunday, they will have enjoyed the experience.
"These players have real pride in playing for Argentina. In 40 years of being involved in rugby, I have seen nothing like it.
"We are balanced mentally. Argentina have had hiccups in the last two World Cups when things were going well.
"Scotland are the most improved team in the tournament, we said that really early on. Frank Hadden is a very astute coach and he has a good coaching team around him.
"They have excellent line-out forwards, a good scrum, cracking kickers and it will be a very difficult game for both teams."