In John Chapter 13, Jesus tells us to wash each other's feet, and that we will be blessed if we do so. Why do most churches do not practice this? How did this relatively easy and straight-forward task not become common practice in Christendom?
This answer does point out there are references of early Christians practicing footwashing, and there are few denominations still practicing footwashings.
Why is this not as common as communion? (Note: I'm NOT looking for why it is not part of the communion.)
When he had finished washing their feet, he put on his clothes and returned to his place. “Do you understand what I have done for you?” he asked them. “You call me ‘Teacher’ and ‘Lord,’ and rightly so, for that is what I am. Now that I, your Lord and Teacher, have washed your feet, you also should wash one another’s feet. I have set you an example that you should do as I have done for you. Very truly I tell you, no servant is greater than his master, nor is a messenger greater than the one who sent him. Now that you know these things, you will be blessed if you do them.
Might it be a possibility that only John refers to footwashing and not the other Gospel writers? If we compare this to communion, communion is mentioned in all the Gospels except John.
EDIT: I do not accept "Our feet are more clean nowadays" as an answer. Even though this might be true, it is still needed to wash your feet once in a while.