Vehicles also lose much more of their value than houses. The second you drive a new car out of the dealership, you are underwater unless you made a good downpay

Vehicles also lose much more of their value than houses. The second you drive a new car out of the dealership, you are underwater unless you made a good downpayment; and it is not uncommon for people financing cars to find themselves underwater on their current one if they want to upgrade (or sell/downgrade to get out of debt). And that is in a good market. If there is a surge in used car supplies, we will see them depreciate even more. In contrast, in a typical market, it is uncommon for houses to be underwater, as they tend to appreciate in value. It took a crisis in the housing market for a large portion to go underwater. A simmilar crisis in a market where underwater is the norm would just push them further under.