That's essentially how buy to let works. As a renter I am paying for someone else's mortgage. If I could get a zero interest (or even normal interest) mortgage guaranteed by the government I wouldn't have to rent and I could retain that value that I have generated for myself. As it stands I work my ass off and make someone else rich in exchange for keeping my chin just above the water line. Housing is a necessity and its profitization is unethical. It amplifies wealth disparities and destroys value in society.