Absolutely Ranascer
I wore Asics gel walking shoes. These shoes have soft soles.
I could feel the hardness of the cobblestones through the shoe soles. Now, that wouldn't normally be a problem, except that on a very hot day, the soles, through heat, become much softer and that, along with the heat penetrates the sole causing the feet to sweat more eventually leading to blisters.
I wear 1000 mile dual layer socks and have never had a blister in over 1000kms of Camino walking. The inner layer wicks perspiration away to the outer layer. Wet skin = Soft skin and is more prone to the rubbing effect of friction. thus leading to blisters. Ouch!
So, my theory is that if the soles of my shoes were harder, the heat wouldn't penetrate to the same extent and the feet would be less affected by tens of thousands of cobblestones that one walks on in some places in Portugal.
Stiffer soles should retain more firmness on hot pathways than gel like soles.
Have I explained this very well?
It is like road walking versus earth pathway walking. Road walking is hard on feet and shoes. Give me a dry earth path anytime.
Cheers
Graham