I wonder how much of this was credit card debt rolled into second mortgages obtained based on inflated real estate values.
Plenty. In fact, while the market was hot, all sorts of folks used their homes as almost a ponzi scheme. They bought a property they couldn’t afford. The made payments for a while by borrowing on credit cards and other loans. Then, they used the new equity to roll all those payments up and often this process was repeated multiple times.
I'll bet a TON. My oldest was part of this - rolling credit card debt as well as an auto and a $36,000 boat. Like others, to get the income tax writeoff as well as enjoy his new real-estate-generated "wealth", although some of this was to take advantage of the lower interest rate. Luckily, when he jumped the tracks like this, he knew it was risky and started doubling up on payments and will soon have the whole mess paid off.
Both he and his wife have almost bulletproof jobs (RR engineer and an IRS worker - and yes, I said "almost"), which is why he temporarily stuck his neck out. Many others were not so lucky - or so realistic.