You’ve got this one wrong on multiple levels.
First they DO pay taxes on their own income.
Second they ARE people legally. Corporate personhood is a hot topic but as the law currently stands when they incorporate (form a body) they become legally a person with duties (like taxes) and rights (like freedom of expression).
Not any corporations I have been involved with. It is a seperate entity, not one and the same as its owners. Maybe I misunderstand your point.