From the physiological standpoint, what happens inside i.e. the cardiovascular system, endocrine system, the brain etc it's all the same. Training for one endurance sport shouldn't different to much from another endurance sport as far as the basic principles are concerned.
So show me the proof i.e. scientific publications on this. Endurance training hasn't changed much in about 50 years or so. Only minute differences here and there. And the general training methods used by all elite athletes are relatively similar. Off season, build up one strength via increasing training volume and than decreasing it as their goal event approaches and making their workouts more event specific.
Than did you ever improve beyond a year or two after changing your training like you advocate now? Do any of your athletes improve at all after a year or two on your program? I'd like to see evidence, like a long term study on a few dozen individuals training like you advocate.