Yes, filtering inputs is important and happens at every level of the sensory, nervous, and brain systems. I'm describing two substantially different levels of filtering and the dancing gorilla test isn't the one I'm focused on here, as it's the high-level attention filtering, as the gorilla is surely not filtered out by the subconscious eye motions (i.e., never seen), but filtered out by the higher-level attention mechanisms. I expect that much ad-blindness is indeed these high-level mechanisms.

What I'm wondering is if after decades of avoidance training, the separate gaze-orientation center (I forget it's proper name right now) which is subconscious and separate from the visual cortex, is trained enough to minimize the eye's gaze in the annoying areas such that the focus point never lands on them and they never get the opportunity to be read (and ignored by the higher level mechanisms). Eye tracking studies using actual eye tracks and not merely heatmaps would tell us the difference - if the tracks still follow the edges, bright spots, etc. into the adverts, then all the 'blindness' is cortical, but if the eye tracks avoid the ad zones, it's been trained down to a lower level.