I just had one of our therapists email me these picture:
The top photo is from a culture that doesn’t wear shoes, and the bottom one is from a shoe-wearing culture. Obviously there is a HUGE difference between the two. Notice on the bottom picture how the toes are all jamming together. The big toe is starting to overlap the second toe. And, there are bunion formations on the feet (left foot has more of a formation than the right). Pretty eye-opening stuff. The feet in the top picture look basically like they were designed to look. The toes are spreading, and the forefoot is able to spread and, therefore, grip the ground better when that person is walking.