Well, Barcelona are definitely big spenders. Half of our players come from the youth teams, but the other half is a group of expensive players bought with big loads of cash: Alves, Ibrahimovic, Keita, Chigrinsky, Abidal, Milito, Henry. Then there's the "middle class", or signings that went well for the relative low cost: Toure, Pique, Marquez, Maxwell, Pinto...
It's a kind of mixed-model, combining great youngsters formed at the club and great players from the world that come here with lots of experience and talent. The mix of all makes the strong squad. Money plays an important role, but not the most important one.
Youngsters play the same tactics and football style than the first team, that's why all young players know how to play in the team and what they will be asked. But there are the great stars from abroad, also, like Ronaldinho or Deco some years ago. It is a known fact that Messi was the shadow of Ronaldinho, big friends, and he was all the time trying to learn from him. Fortunately for us, he learnt most of the good things from him, only. And Ronaldinho and Deco were holding all the pressure, making the youngsters more "free", just as now Xavi and Messi hold the pressure and people like Pedro or Busquets can develop more "free of charge".
I think it would be interesting for Arsenal to find those "holding" players that would free the younger players.
I doubt Messi would have developed so well in any other scenario.