If putting those 12 hours towards making food and shelter works then it’s not fair. If you need multiples of those 12h to make yourself a shelter, you’ve just invented capital.

In real terms: if every renter received equity in what they pay for rent (- maintenance) then housing would be more fair as both rent prices would come down as well as purchase being more affordable as landlords start selling the stock

Edit: note that I guess i’m replying to both you and the original commenter