walter samuel, figo was sold too soon (still superb at inter... became a legend there), roberto carlos was sold when he still had 3 seasons of great form left, seedorf, enrique, sneijder who was replaced by kaka... and who both had opposite fates.. sneijder went to the treble, kaka never returned to his best, cambiasso, luis aragones, canizares.
that's the world class players that weren't adequately replaced, or were sold with poor judgement as they all went on to be extremely successful (or showed they could still remain at an extremely high level for a sizeable amount of time, in the cases of figo, carlos.
that's not to speak of the sublime talents that were never given a real chance... the likes of borja valero, mata, eto'o, negredo, van der vaart, cassano, (robinho?), huntelaar (arguably not madrid quality, but still one of the best finishing 9's in the world).
not that i think this should be held against madrid, although it is a quite remarkable team of rejects when you compile it in the whole.