MoPo,
The way you phrase that EPO "won't work as well on highly trained, altitude acclimitised athletes," is not much different than saying anything has less effect on "highly trained, altitude acclimitised" athletes. For example, a 20-mile per week runner will have a much greater improvement on race day if they add 10-miles to their weekly volume, than if the elite added 10 miles per week of volume.
EPO works on every athlete. To the degree and how that changes is probably going to require a whole lot of testing. If you go to World Athletics and look up the bio of athletes, most of the time you can see approximately when they were caught doping and when they had a sudden jump in performance.
Kipsang did not test positive as far as we know. We know he tampered and missed four tests in 12 months. What he was hiding and avoiding had to be performance-enhancing drug usage. WADA, and now AIU don't take lightly the legal process of suspending someone and effectively ending their career, reputation and removing some past results that may have implications to do with re-assigning medals and trying to get prize money back.
Although we are getting numbed and bored by all the positive tests, athlete biological passport anomalies, missed tests, tampering etc, it is a very big deal to make the decision to dope and it is a very big deal to hand someone a provisional suspension and it is also a very big deal to go through the appeal process.
Some countries are making PED usage subject to civil law — a criminal conviction can happen. The prize money taken is theft. Re-assigning medal is nice, however, the moment is forever gone in the case of when someone else should have been standing on the podium listening to their national anthem with a gold medal around their neck.
We shouldn't discuss doping as light banter. Consider the fact that qualification standards are set based on recent performances. So, false benchmarks. It is absolutely unfair and unjust.
Take the case of the women in the 1500m event in the London Olympics. Those who did not make it out of the semi-finals were beaten by doped athletes and we know this now. Half of the finalists were caught doping. How do you go to a 4:02 runner who didn't make it out of the semis and figure out that they could have/should have competed for a medal and calculate the odds that she could have medalled. What ifs. All gone. Nothing you can do about it.
There is a reason why EPO is banned. There is a reason why WADA, AIU et al don't write, "banned substance, except for the top .01% who are free to use EPO because of the limited benefit."