Generally speaking, clubs need several outstanding prospects in their system to hope to produce one great baseball player. It’s the nature of potential that there will be some spillage on the way to actualization. The game is insanely difficult, the body prone to breakdowns. There will be wreckage along the way. Looking over historical lists of “Best Prospects” for any organization is apt to produce that familiar “oh I was REALLY high on that guy — I totally forgot about him!” sensation.
It’s really nothing short of shocking then to look at the Giants’ systems from 2005-2011 and realize that the six prospects who topped their system went on to produce an extraordinary 160 career fWAR — with that production coming (to date) — ENTIRELY as members of the SF Giants (the positive production anyway; Tim Lincecum did contribute a sub-replacement year to the Los Angeles Angels).