I think the key words here are:
These data suggest that high-intensity training is more effective in improving cardiorespiratory fitness than moderate-intensity training of equal energy cost.
But, if you were to do long rides at your
best pace for the distance, your energy cost would be higher, your ride would be "high aerobic", and you would not be able to do the same amount of work if it were all high-intensity.
Of course, this all depends on whether you are a road racer, crit racer, mountain biker, or track specialist. Whatever the case, you need to provide training that is specific to the discipline.