The housing boom fueled by rising debt and leverage

The housing market's rise was fueled by rising debt and increased leverage (real estate firms taking on debt to acquire land, and households buying homes through mortgages).

But borrowed money must be repaid.
A sharp drop in housing prices would trigger a debt crisis, shaking the very foundation of the economy; whereas a stock market decline only sweeps away those who sell at a loss.
After an asset bubble bursts, the greatest danger isn't falling prices—it's that assets are built on debt, and price declines can collapse the entire debt chain.