sososo - you've been a tad selective in those PBs in A - prob overlooking some high level XC results that perhaps better reflect what upward performance trajectory these guys were on (v much so in de la Ossa's case); 2 - in several cases the relatively modest 10k times came at stages where the guys were more focussed on 3k/5k, at which distances their PBs better reflected their 10k potential.
Just as anecdotes that prove nothing either way, many of the big hitters changed in their mid-20s from being in full time employment (in some cases very long hours), often in light industrial work, with very little cutting edge support service, to full time runners. They often identify being able to sleep up to 12 hours per 24, instead of their previous 6 or 7, as a key factor in addition to the step up in quality and quantity of training. In a RFEA seminar Q+A with Alberto Garcia's coach in c 2000/01, a couple of folk query precisely what changed in the big leap forward and, with hindsight to him getting caught for EPO, there was clearly an undercurrent in the question and the not-so-robust reply. With the World 5k heats set for tomorrow, Garcia has detailed in recent interviews that his key track sessions this season suggest he is in best ever shape.
Elsewhere on the Letsrun boards the mighty Jon Brown suggests that the large majority (but most definitely not all) of elite SPanish runners do what they do clean, and I've heard similar at first hand from another GB top flight runner who spent over a year training day in day out with their big guns. It's depressing,most acutely so for those of the Spanish elite who are clean but well aware of the rumours tarring them all with the same brush, that Garcia, nor indeed the other lower profile runners who have been done for EPO aren't the only bad apples.