A lot of good points made here. I definitely don't think building a team and spending money have to be mutually exclusive. The key is having a clear idea of what sort of team you want to have and what sort of football you want them to play. Then every decision, from youth recruitment and development, through training and coaching and onto scouting and transfer business should be made to compliment that idea (or "philosophy" before that word was ruined for us all).
Barcelona and Bayern Munich can spend large amounts of money because they have that structure set in stone. They aren't throwing money at silly targets for the sake of it. Each signing is carefully thought out and made to address a gap they have identified in their set up. They have such a clear and well understood outline of exactly what makes up their squads, that it is immediately obvious to them which areas need improving. This helps with preparing and introducing youngsters, as well as lessening the risk of venturing into the transfer market.
Since Fergie and Gill left (or looking at signings like Berbatov and Kagawa, possibly even a little before), we've had no such idea or direction. It's hard to know what we need because we don't know what sort of team we are. It's entirely possible that players like De Gea, Darmian, Smalling, Blind, Shaw, Schneiderlin, Schweinsteiger, Herrera, Mata, Memphis and Martial could make up a top class side under another coach or system. You could add Rafael, Di Maria, Kagawa and Hernandez to that list above and having seen those players leave, and others come in and struggle, it's hard to have confidence that any top players we bring in won't struggle just as much these days.
Our recent approach seems to mirror that of Real Madrid's. Offer massive amounts of cash for marquee players at their peak. Quite aside from this strategy not having brought Madrid the success they might have expected with the money they've spent, it also ignores the fact that in Madrid; the city, the climate, the cuisine and the language is all more attractive to players from Southern Europe and South America. We can compete for players from the UK, Northern and Central Europe but in recent times, these regions haven't been producing the same level of world class talent.
None of this needs explaining. In fact, I feel a bit silly having typed it all out seeing as it's about as necessary as telling your grandma how to suck eggs, but it beggars belief that the people running the club can't see this.