Over time, bare feet will develop calluses (just like manual laborers will develop them in their hands). I have the same kind of feet as your mother as I can comfortably walk on most surfaces barefoot, including snow. Eventually my feet do get cold walking in snow so I don’t do that for very long!
I never wore shoes except for school and church growing up.
Even in the snow I was comfortable barefoot.
Each year they would spray tar on the dirt road in front of our house to keep the dust down. I would walk in the fresh tar barefoot as it put a thick layer on my feet that protected from thorns.