However other foot problems can still cause a lot of problems for children and adults. Children born without toes may have balance problems and difficulty learning to walk and feet are easily injured. Even seemingly minor things like fallen arches can limit mobility in a small way, though most problems like that are correctable. (For help with minor foot problems I strongly recommend a book called Fixing Your Feet by John Vonhof.)
And there are many major foot problems that seriously limit people's lifestyles and are certainly disabilities.
Fortunately we live in the 21st century and many things besides crutches and canes now exist to assist with mobility problems. In past posts I've mentioned some of the contraptions like artificial hands that can be electronically controlled by the brain. While things like that are expensive and not options for everyone, foot problems are much easier to deal with than they used to be.