What sort of adaptations? As far as I'm aware, adaptations are the result of significant stress. What are the stressors of a "long easy session"?
At any rate, my post was about physical fitness and health, not how to become a competitive athlete.
Many competitive athletes are not fit. A marathoner who has no muscle mass and who is physically weak is not fit--regardless of the fact if they can run a 2:15 marathon. Said marathoner is not resistant to adversity, e.g., consider how they'd do on a wasting disease like cancer versus an athletic 215lb male.
What competitive athletes do generally is not a useful consideration when deciding on training modalities. Assuming that what the pros do is effective because they're pros is logical fallacy and, regardless, these people are (genetic) outliers with differing goals.
Low-intensity, long endurance cardio is adversarial to increasing strength. If you want to be a competitive endurance runner then, sure, you need to adapt your training and you will need to do long endurance cardio. If you're just an average Joe who wants to be healthy and fit then it is not in your interest to do long endurance cardio. Injury rates are higher, it makes it harder to become strong, and many of the resulting adaptations are undesirable.
