I hadn't thought much about it, but looking at the new thru axle hub with the 9mm adapter installed, it looked quite wide. I took out my digital calipers and measured it.
The first picture is of the 20mm thru axle.
Second picture is the measured width of the axle. 120mm
Third picture is of a standard front wheel QR hub from one of my Tidalforce bikes. 100mm!
The 20mm front hub is 20% wider than a normal QR hub can handle!!,
Surprise, surprise, surprise!