While it may be true that a 100 mm ski will require a few more degrees of rotation to reach the same tipping angle of a 65mm ski, that only equates to about an inch or two more of lateral “knee wag” in a retracted turn. This is a movement for experts that is primarily funded by the ankle, ski rebound and ground force reaction and very little muscular effort. For me, that doesn’t slow my tipping very much at all. However, to create those quick tipping forces, it is the accumulative elements of flex, torsion, rebound, side cut and, least influential, width, that make a ski quick in general that is what really makes the difference in actual edge to edge speed. If you are thinking about strict tipping geometry, based on width alone, between a 70 mm ski and a 90mm ski, you are wasting your time.
It is very typical that the wider the ski is, the softer the shovel will be (both flex balance and torsion) and the less turny the side cut will be. This means the ski is less responsive in turn initiation than an SL ski in a way that relates to overall quickness. For me, it is these two attributes that typically accompanies ski width that makes the actual difference in making a ski slower from edge to edge.
Ultimately, which ever ski I am on, quickness comes from technique and making the ski work for the skier rather than the skier working for the ski. The difference is weather you are using your ankles to tip the ski under you and whether you are using angulation for crossunder mechanics rather than using inclination for crossover mechanics. In a large radius crossover turn, there is time and space to use crossover inclination where width has little or no influence but, if we are looking for quickness, we are not inclining, we are angulating our legs under the CoM.
If they made a 100 mm ski with a stiff shovel and deep side cut, it would “get over” quicker for me than a skinny noodle 65mm ski with a soft shovel and shallow sidecut - for someone who knows how to get the ski to do the work. Ultimately, if I had to guess, the speed edge to edge is 90% skier technique/ability and 10% ski, the lion’s share of which comes from sidecut, torsion, flex balance and rebound leaving very little of that influence to actual width. Also, actual ski width alone only effects degrees of rotation required and has absolutely no influence, by itself, on edge grip. I have no idea where those comments are derived. That is the reverse of my above comments regarding separate but complementary factors such that a narrow ski is going to be made with a stiffer shovel and deeper sidecut that increases the overall quickness of a ski far more than the narrowness of the waist.
People that are honing into the width, are only looking at the face value of elements which, by themselves, often makes very little difference at all. I think they are locking on to the mathematical geometric proof it brings with it rather than the actual influence it has in technical performance. It is like saying a yacht tips faster mainly because of the width of the hull which is really only a small part of all the attributes that tip a yacht faster such as the keel, rudder, masts, sails, crew speed and all the power these produce from the wind and water.