OK what if a billionaire built a 26 mile "superloop" on the Bonneville Salt Flats using the same material as the Rieti track.
Then, you had a pace car that drove along said track at exactly 1:59:59 pace.
No drafting. Just a pace car that went at EXACTLY sub-two pace.
Then, you had perfect weather and an East African who had been training perfectly for the marathon since birth.
How much faster could a marathoner like Kipsang run if something ridiculous (and completely unrealistic, of course) that way?