Spot on. I worked as a volunteer with a BofA somebody at the start of the meltdown. They were stunned and flatfooted as cars and credit card payments rolled in like clockwork...and mortgages went unmet month over month. The lenders had no plan, because, as you mention, they had never seen anything remotely like this.
There was a funny commercial I heard on the radio probably 30 years ago. I think it was a debt consolidation service or something like that. I don't remember the exact setup but a couple were trying to decide which bills to pay, and all the bills had squeaky voices saying "Pay me first!", "No, pay me first!", "No, me!"
Then a deep voice said "NO, I'LL BE PAID FIRST."
"Who are you? Who are you?" all the other bills squeaked.
"I'M THE MORTGAGE."
Then the other bills started saying "Pay me next, pay me next!"
It was pretty funny, and indicative of the debt priority thought process back then.
At some point in that last downturn people stopped thinking of the mortgage as the bill that absolutely had to be paid, and realized they had to be mobile in order to keep or find work, and could live in their car, so the car got paid first. And they had to be able to buy food and stuff, so the credit card had to be kept alive. If the house was under water anyway, why keep paying on it? So they'd live in it for free until the eviction notice came, then leave the keys on the counter and walk out.
The loan industry was slower in figuring out that shift, or at least never thought it'd get to that point. House prices never drop, right? So who would walk away from a house with equity?