I always thought this was a huge issues with a lot of AD champions. At some point late game, they just become Auto attacking bots.
Caitlyn will Never Q, Twitch E, and some others during team fights. (they use them before or after fights or if they just cannot auto any more, Much like corki, it just dips their dps IF they use these abilities instead of auto attacking.)
Because they just dont scale with the builds. LIke crit, and attack speed. Their abilities cannot crit. and they dont build a lot of AD.
For your build, Without Sorc Shoes, and Void staff, I would say that would play a large factor.
However, Corki doesnt Really Q in fights, he only does it if they exit LoS.
I would LIke if adcs as a whole got looked at, to help their abilites do better damage, so they can have better builds, and take some power out of their autos.