His VO2MAX measurement was in the group of highest recorded ever for Norway, which includes almost exclusively XC skiers. And that's without being super light/skinny! Imagine what Salazar could make out of him once he puts him on his usual weight reduction PEDs.
J Ingebrigtsen ran 13:02 as 18-year old - there has NEVER been a 18- or 19-year old that has run a faster time, EVER.
Look at some of the best Western 5000m runners in history - Solinsky, Jager, Mottram, all were taller AND heavier than Ingebrigtsen.
His 400m PR is 51.03, the fact that he can run a 1:49 800m with that is already showing how weak his speed is compared to his endurance. I agree, he will never run a good 800m time, but in the 1500m and 5000m he has HUGE potential, by just becoming the fastest runner in the field. Cheriyots speed will be useless when Ingebrigtsen runs 3:27 or 3:28 on a constant basis and in the 5k he is nowhere near maxed out.
El Guerrouj was not a speedstar either in the 1500m, Ngeny had much more speed but El Guerrouj only lost once to him. Once J Ingebrigtsen gets mentally stronger like El Guerrouj was ("fearless running") and does harder workouts (El Guerrouj's workouts were legendary) I don't see why he shouldn't be able to get his time in the 3:27 range.