Fabregas came to Arsenal when he was 16 and he's now 24. So even though he trained with Barcelona before that I would say he is more a product of the Arsenal youth system than the Barcelona youth system.
If he came at a certain level, trained at Arsenal for 2 years and started playing a completely different player, maybe, he joined, he was excellent, he started within months, became first team very quickly and looked brilliant from the day we signed him. He was NOT a product of the Arsenal youth system in any way at all, if we signed him at 24, and he played almost immediately and was 32 now we wouldn't claim he learnt his trade or became great at Arsenal.
Anyway, who cares, as for barca and their spending, compare their wages, and Real's and how much both teams have spent on wages during the times listed, IE real since 2005, and Barca since 2007. Basically both teams will have spent more on wages than transfers, as even Chelsea, and City(in a couple years) will have.
Barcelona do spend, heavily, very very heavily, its just on wages. Transfer fee's SHOULD be completely ignored, they mean next to nothing, wage spending(and ability to sustain it) is almost completely where success comes from.
Just about any player in the world COULD have been grabbed for free at 16, or bought later for 80mil, thats timing, good business, luck, preference of players to play for a certain team, etc, etc. Wages don't really get effected by any of that, Messi/Ronaldo are on flat out sick wages, and frankly deserve to be over many other players who don't deliver for the wages they get.
The thing about it is, a 150mil a year wages type team WILL consistantly win leagues vs a team spending 30-80mil a year, that is proven time and time again.
But once you get above 100mil a year, while the wages can go up dramatically the quality and ability of a team doesn't. You need a team that puts you in the ballpark, and that will cost X amount, but as with all sport theres errors, good years, bad years, injuries.
Why do people leave Barca, because if a team has the 20 best players in the world, 9 won't get played that often, if a team has the 30 best players in the world 9 won't get played that often and another 10 will barely ever play. So no matter how much money a team has, or how much they dominate in spending, the best players will spread out because they want to play football.