Unfortunately, through policies like the Community Re-investment Act, banks and mortgage companies were basically forced to lend money to the absolute worst credit prospects imaginable..knowing the chance for repayment was zilch. Without trillions made in sub-prime loans, we wouldn't have had Wall street packaging this crap as investments and at least one major cause of the economic meltdown would have been averted. Amazingly, Obama wants to expand this act even further.
You only got a part of that story right.
A ton of foreign money got dumped into the U.S. housing market (don't ask me for exact figures), which helped to artificially inflate home prices in certain areas. This was aided by the devaluation of the dollar vs foreign currencies.
Lenders weren't forced to make bad loans, but *chose* to because, in the end, they were going to end up with any amount of cash paid in, PLUS the properties themselves. Realtors, mortgage brokers, banks, and even appraisers were all in on it.