Why exactly no stomach drop?

Hey, so my understanding is that for the vast majority of people, there is little to no stomach drop from a traditional skydiving exit. I've heard a number of competing explanations as to why this is...

Some people say rollercoasters accelerate you faster than gravity.

Some people say it's psychological and since you're so high up you feel nothing.

Some people say since the plane is moving you're just changing directions (but you're static inside the plane.. so when you drop you physiologically experience movement backwards in the form of drag induced inverse acceleration and downward acceleration).

My current working theory is that you experience less than 9.8m/s² downward acceleration due to being able to air brake off the relative wind while on the hill.

This would explain why some freefly exits and balloon jumps would cause some stomach drop sometimes.

Thoughts?