Think it's more the number of T20s that Root actually plays in. He's the same age as Williamson and a year younger than Smith, yet Williamson has played over twice as many T20s as Root and Smith has played nearly 3 times as many.
It is the players who set their base price isnt it?
I'm still not sure how I feel about these T20 leagues but I hope Root and the English lads get picked up, I think it did Stokes's game the world of good going last year.