This is a terrible idea. Why further punish kids for the success and efforts of their parents? Even if this isn't outright lowering the score of high-achieving kids, this is lowering the worth of their accomplishments in the greater college-admissions market.

I think the fundamental difference here is that football is inherently competitive while math is not. While it's true that football coaches have incentives to produce great players that will eventually play in college/professionally, the most immediate incentive is to have players that will win games. Math teachers have no similar competitive incentives. The "passion" that Urschel mentions here is probably largely a product of the desire football coaches have to win every Friday/Saturday night, and this is reflected in the way that they develop kids. Additionally, Math teachers have to both teach kids AND grade them. This limits how much a teacher can really be "on your team" because they need to retain the ability to give you a bad grade. This is true with football coaches as well, but with football there is always a bigger "bad guy" (other teams/players) so a good coach is always more aligned with and close to the players.