you can coach throwing mechanics. you can practice throwing accuracy. you can work out and build throwing power. but guts, determination, and the ability to perform well in spite of adversity are unteachable things that Tebow excels at, and meanwhile Gabbert has yet to show even flashes of any of those. Tebow pulls out two-score wins in the last 3 minutes of the game. meanwhile if it's halftime and the Jags are down by 4, Gabbert sucks even worse than he did in the beginning of the game.
If Tebow were a pitcher, he'd have a .120 BABIP. It can't last.