The more upright the bike, the more throttle you can use

A tire has a limited amount of grip, and it has to be shared between cornering and acceleration or braking. Deep in the corner, most of it goes to holding your line, so little is left for the throttle.

The more upright the motorcycle becomes on corner exit, the more grip can be used for acceleration.

Body position helps too: by moving to the inside of the corner, a rider can follow the same line with less motorcycle lean.