Man Utd, Chelsea, Liverpool and fans of the rest of the premiership should really face facts. Although the stock of the premiership has risen a lot since it's inception and it's fanbase has mutliplied thanks the global tv rights, the fact still remains that Real Madrid and Barcelona are the two biggest clubs in the world.
When I say biggest I don't mean in terms of turnover, it is more of size, history and the magical lure of the club. And yes Man Utd and Liverpool have that as well and their are many fans from Africa, Asia and North America that would dream of pulling on a shirt of a premier league clubs as in those parts of the world the premiership is king.
But notice I left out the two most important regions in terms of football, that of Europe and South America. Youngsters in Brazil and Argentina dream of Real madrid and Barcelona, they are what they aspire to. Not a suprise either in both cases as Cambo pointed out, young fans look to their idols. The most famous Brazilians and Argentinians to ever play in England are Robinho and not really anyone else (famous wise) and for Argentina, Ardiles or Tevez. Where as Spain has had Maradona, Di Stefano, Romario, Ronaldo (the fat one) and Messi to name but a few.
In terms of the rest of Europe the allure is quite similar in France they Zidane, Holland have Cruyff, Bulgaria Stoichov, Hungary Puskas. The list goes on and on. The history of foreign players in the Premiership is relatively short and considering most players were born in the late 70s early 80s what should also should come into consideration is that they would most likely start watching football in the mid 80s without English teams involved in Europe because of the Heysel disaster.
Yes money and tax is important. Some players will choose money. But footballers once all had a favourite team, a shirt they dreamt of wearing. Unfortunately for the Premiership that shirt was more than likely white or red and blue stripes.