In contrast, the very different "mortgage backed securities" are debt instruments that banks can hold off of their own accounting books...allowing them to become extraordinarily leveraged.
What you don't want is a Zimbabwe printing press at one extreme, or a Depression-era "lend no money" at the other extreme.
You want that happy middle ground. You can't just shut off the entire real-estate market (unless you want to live in the Middle-Ages). So new loans need to be made.
” Depression-era “lend no money” at the other extreme”
That gets my vote.
No one should everget a home loan without putting at least 20% down and adjustable rate loan should be illegal.