A better metric is homeownership to me. Someone who is middle class is secure and doesn’t have to rent nor pay debt. They only really have to work when it’s mutually beneficial. That is basically impossible to achieve in the modern world with the hundreds or thousands of micro taxes and cartel controlled corporate markets and complete lack of land for the lease it’s to live on without virtual indentured servitude. Even if you did spend your entire life buying a house the state would just take it away from your children with the brutal taxation. Without a home you are always going to be a slave and have to work at any shitty job just to have food and a roof over your head.