Dumont went further, fell harder and sustained worse injuries, Tanner is still nursing his wounds because he cant get over his fall from the top of skiing.
Seriously, Dumont fell 200 or so feet, Tanner only went like 120. Chads gaps landing is about 20 or so feet down from the takeoff vertically, Dumont landed about 100 feet vertically down. Tanner did hit a wall with little softening, but still, Dumont hit hardpack.
People hit chads all the time, Candide decked into the landing way back when 3 times in a row, then overshot it massivly, landed on his back and then proceeded to whip a d-spin over it. Granted, there was a lot more powder, but still, in terms of parabolic arcs, Chads doesnt compare at all to what Simons was.