The average American moves 11 times per life, or maybe once every 8 years. That means 1/8 of homes, or 15.75M homes, might be "vacant" just to support people shuffling around

That assumes it takes a full year after buying the property to fully move into it. If we cut that number in half ( 1/16 of homes, or 7.87M homes) that provides more than enough homes for the homeless population and assumes 6 months for people to move which is still absurdly long.