> should only be a small fraction of the total volume

Which is? Lot's of people are happy to rent, want to rent, will never want to own a home, want mobility, etc. I rented for nearly 20 years and only past few years went into situation where I want to buy a house. Should I be denied renting?

There's obviously premium to be paid while renting too. There should never be a situation where rent is cheaper than mortgage.