1- If "the wide-ranging evidence suggests doping is an increasingly sophisticated process with a lot of science that has gone into it", do you really think the most part of users are athletes with a very little income, that for having a real support from "doping scientists" have to pay more than what they can earn in one season ?
2- Coaches and trainers can't measure the benefit, for the simple reason that there are coaches without any ethics using doping (and in this case they don't know where their athletes, if training clean, could arrive), and coaches with deep ethic, who only know the effect of training, and of course can't know where their athletes could arrive WITH doping.
3- It's true that doping greatly exceeds the numbers of those caught, but this doesn't show that is far from being an amateur practice, and is enabled by professionals for professionals.
Italy is one of the Countries with the higher number of doped. Do you know why ? Because we have the Anti Drug Police that, investigating against the groups selling doping, is for law authorized to do antidoping tests to all people frequenting gyms, if they have the suspicion that the gym is a place where doping can be sold. This means the 99% of doping cases in Italy are from amateurs, or not agonists who takes doping only for showing better muscles on the beach.
Put in your mind that Kenyan athletes running 2:08 / 2.27 (W) in Marathon, ARE NOT PROFESSIONAL. They don't have a contract with any Company, can run one competition per year, and in the most part of cases DON'T HAVE AN OFFICIAL MANAGEMENT.
They are FARMERS, who train in big groups without a personal program, and sometimes are lucky to find some solution for going to compete in Asia or South America in small Marathon or HM.
These athletes, when honest, have the same behavior of every normal Citizen when sick : they go to the pharmacy with the prescription of a doctor, and, because the most part of medicine in Africa come from Asian Countries, in all these medicine there is some small percentage of steroids (from that reason, a lot of banned for nandrolone and similar steroids).
Other athletes, if want to cheat, ask simply, individually, to some friend which type of doping can use for improving, having "faith" in what they hear or read.
This is the reality in Africa, reality that all people speaking about doping in LR obviously don't know, thinking every part of the World can have the same situation and the same mentality.