Yeah but you can also only race who is there. Guys like Al Sal, Shorter, and Rodgers were argueably the best marathoners in the world for a couple of years (top 5 is pretty undebatable). It is sort of a stretch to put Rupp in the world top 5 unless he drops some 2:04 type time.
It is both easy to overweight times (2:052nd) and comparison to peers (ARs). And how much do you favor multiple wins (i.e. Bill Rodgers) versus high peaks (Say Salazer with a WR:)) How you balance them is sort of personal.
Meb and Shorter are pretty closed. Do you favor Meb cause the fields were deeper or do you take Shorter because he won the big one and set the AR. I take shorter but the otherside is defendable. Or do you just focus on times so that KK + Hall are 1+2 on your list.
Unless Rupp does something crazy (i.e. he wins in say 2:03) I find it hard to imagine him passing either of them tomorrow. Win tomorrow in a decent time (say 2:06) and then has another couple great runs (say top 3s, sub 2:07) we can start talking about Rupp being the GOAT.