Why 36MP at 100% looks less sharp than 12MP a 100%

I've drawn up a diagram depicting a theoretical set of points in space and how those points would be sampled by both a 36MP and 12MP sensor. The purpose is to demonstrate why a 36MP image appears less sharp/contrasty at 100% than a 12MP image by depicting a 3-tone edge transition, a transition which appears crisper on a 12MP image due to coarser sampling. The three center points have values of 0, 64, and 128. I've depicted the sampling of those points on a 12MP sensor as a single pixel whose value is the average of the three (64).

Does this depiction make sense? Is it accurate? I realize a 36MP sensor doesn't have 3x the horizontal pixels of a 12MP sensor, so the diagram takes some liberties for the purpose of illustration.