Well, we have arbitrary rules, that produce a result close to an arbitrary timespan. Then you change the rules in a way that breaks the timespan, in a way that is compatible with an ill defined cultural expectation what is essential and what is incidential of the original rules.
I mean, of course to I realize that a fan would violate some expectation of long distance running more severly than pacemakers and a specially prepared course, I just say that to call it sports, other teams of runners should be allowed to compete according to the same rules.
They didn't change the rules. That is why it is not a world record. Because they broke specific rules to see if it was possible at all before attempting it in record eligible conditions.
The importance of the attempt is that nobody knew if it was actually possible to run a marathon in under 2 hours without performance enhancing substances, i.e., if the theoretical estimate was unattainable in real world attempts.
The use of the pacing car and bringing the water to him are the only things that would not be replicated in a real world race, since runners already pace and draft off each other in the lead group of a marathon.
Expect to see several attempts to come close to 2 hours on the best several Marathon Majors races with a likely would record in Kipchoge's next competitive marathon.
I strongly suspect that marathon runners always try to be very quick. (At least if they actually try to break a world record.)
However, a very concrete example would be bringing him water, as opposed to slowing down and grabbing it. Something that I can easily imagine brings 20 s, and therefore we still do not know, if a 2 h marathon is possible.
I mean, of course to I realize that a fan would violate some expectation of long distance running more severly than pacemakers and a specially prepared course, I just say that to call it sports, other teams of runners should be allowed to compete according to the same rules.