It doesn't really work that way. The problem with the US (I don't know if it's the same in Australia, but given the social similarities between the two, it probably is) is precisely the youth system. Not so much the system itself, but the way the game doesn't really exist outside of it.
The biggest talent producers for a long time have been Brazil, Argentina and in Europe, the Netherlands. Those are places where the game is being played on the street, from a very early age, and where the technical level on the streets is very high. It is only after kids have played on the street and developed basic ball control skills and vision for the game that the best of them get picked by youth systems and taught tactics and developed further. And they usually don't stop playing on the street for a good period of time after that. Note, however, that the popular myth that Brazilian players get picked from the beach is exactly that - a myth; they spend a lot of time developing in the youth system, but not all of their development happens there, which is the point
It is the same everywhere else, it is just that those places have the best combination of highly developed street football culture, scouting system and large population base to pick from.
Now in the US, kids usually get shipped to the "soccer academy" at an early age and they begin playing with football shoes on the big pitch, which produces good players, but will never produce truly great players. What the street football gives you is, first, close ball control and dribbling skills, as you typically have to find your way through a dense forest of bodies in tight spaces, and because you don't play with football shoes, you develop a much better touch for the ball (this one may be hard to understand unless you know from experience, but it a lot more important than it seems); and second, flair and creativity, as you are not constrained by tactical schemes and by being told how you have to play. From a large pool of kids who have developed those skills, it is always possible to pick the ones with the best potential, then develop them physically and teach the tactics.
You get none of the above if you have had your entire development as a player happen on a full-size pitch, with the boots on and with a coach around you telling you what to do. What the US approach produces is players who are good enough, who can run, pass and shoot, but who are lacking those special extra qualities that make a player truly great. Such a system will never produce players like Ronaldinho and Messi.
To illustrate my point even better, it is useful to remember that what has happened in England in the last few decades has been a transition from picking talent from the street (and from playing on the street) to developing it in academies. This coincides with their national teams slipping further and further into irrelevance.