The main thing commentators here are missing is that GMs have more confidence and do not repeat their analysis, but amateurs (strong club players included) typically re-analyze the same lines over and over. That alone would account for far stronger play with fewer moves considered, if you count the same move multiple times, which you should!
Also, Jonathan Rowson (Scottish GM - peak about 2600) describes his training matches with Mickey Adams (peak #3 or so in world - 2760), and says pretty much the same thing. Most of the time he asked “what about this line I rejected”, the answer was usually “I hadn’t considered that”.
Those critical moments are a big part of the difference between a GM and a good club player though. If a GM was somehow handicapped to not calculate such tactics, I think lesser players would be able to draw games against GMs much more often.
I agree that GMs can avoid calculation in many positions (e.g. openings as you said), but the value of broader and deeper calculation is still huge in chess.