If Man United put up market rates for top tier talent between 2005-09, I believe we would have beat anyone to top players.
It wasn't that long ago that Heineken preferred a move to Liverpool to Real.
Real and Barca have benefitted hugely from the halo effects of Messi and Ronaldo. They have spent heavily, and have fantastic teams.
Much of this was driven by a gold pot of Spanish talent coming through in the last ten years.
Bayern have also massively benefitted from a golden generation of German talent.
In a few years, if we have a strong team competing for trohpihies, I fully believe - with the ever increasing pull of the PL - we will compete with anyone for the very best players in the world.