A large amount of information important to her escape potential is omitted in your example.
In a very common situation, Kalista has her berserkers and a couple daggers at least early on so she has the AS to leap all over the place by the time most junglers will be ganking often.
Additionally, Yi is probably one of the best champs for catching her, since he just has to get close enough to use alpha strike, which removes him from the map, so once he's in auto range he can close the rest of the gap, whereas Udyr, Rammus, Voli, etc. just have movespeed boosts to close the gap, which Kalista just fuckin laughs at.