Every individual responds to and recovers from the stress of training differently.
Consider all the things that seem to be true about Kiptum and his training that have contributed to his success and ability to cover many miles per week in training.
He is extremely talented.
He started training for long races (half marathons) at a young age.
He grew up and lives/trains at relatively high altitude.
He started training with elite runners at a young age. (like Jakob)
He started running long (half marathon) races at a young age.
He is only 23 but has been training seriously for 10 years. (similar to Jakob)
He is only and likely is more fearless and can adapt and recover more quickly than older runners.
He runs trains by running high mileage at fast paces.
He may respond to high mileage at fast paces better than others.
He may be a super responder to super shoes.
He may wear super shoes for most/all of his training (Kipchoge seems to be wearing super shoes during all recent videos of him training).
Super shoes may help him train longer and faster than regular shoes.
Super shoes may help him recover faster than regular shoes.
Super shoes may allow him to cover more miles in less cumulative time than others wearing regular shoes.
He does his jogging easy runs at a relatively fast pace, so he covers more miles per time spent training than if he ran slower.
He does many fast continuous runs at fast paces, which helps him accumulate many miles per week in less time.
His training is specific to the marathon (multiple sessions of 30-40k at near marathon race pace.)
When he does hard training he is running alone (training alone makes it easier to set records and win alone).
He does not feel pain during marathons.
He focuses on running, only runs, eats and sleeps (similar to Kipchoge)
He may have already made more money from running than he ever dreamed possible.
He may not care about longevity in running.
Rest is not built into his training, he rests only when he is tired.
He may believe it's better to burn out than to fade away.