I am pretty sure the author is describing a well understood limitation of Elo, they just need a tiny bit of connecting to models.
Elo can be thought of as an approximation to item response theory models [1]. These describe skill as normally distributed, and whether one person will win using a logistic function (not exponetial).
I think what the author has keyed in on is that afaik in simple Elo there is no slope coefficient for the logistic, but in general IRT models there is (called item discrimination). So in Elo you can't learn that flatter curve they show.
Elo can be thought of as an approximation to item response theory models [1]. These describe skill as normally distributed, and whether one person will win using a logistic function (not exponetial).
I think what the author has keyed in on is that afaik in simple Elo there is no slope coefficient for the logistic, but in general IRT models there is (called item discrimination). So in Elo you can't learn that flatter curve they show.
[1]: http://hvandermaas.socsci.uva.nl/Homepage_Han_van_der_Maas/P...