Yea it is pretty much undeniable that the largest cause of flyers is the guy behind the trigger, but there are also other reasons.
I think the 10/22 first round flyer is headspace related if you get the bolt re-headspaced and the first round flyers are diminished the bolt pinning is supposed to help roud to round primer strike, the more consistant the strike the more uniform the ignition.
As for loads most of us have probably seen that group a couple good and close and one off on it's own. there is a temptation there to call it shooter error and call it a good group.
For the last while I have been using the "Optimal Charge Weight" for load development. the theory is a shock wave caused by ignition reverbarates up and down a barrel. When the shock wave is at the muzzle the accuracy is less than if the shock wave is at the action end. The trick is to identify the band of charge wieghts that produce the right velocity where the shok wave is the furthest away from the muzzle (more stable = more accurate).
Load that are close to edge of the band through normal pressure variances throw a shot out side of the stable band producing a flyer.
Ideally using the ocw method you find the middle of the stability you load up there and no matter what conditions your in (hot antelop hunt of freezing deer hunt) you POI won't change.
