I have no reason to believe the family is irresponsible, w/o further information. I am pretty sure that they didn't ask for a ridiculous house, even if they got one.
Now, the bank who gave them a 450K loan....
These folks may have taken the leverage given them, and set themselves up to never be poor again, for all I know. Or, they may have squandered it all on trips to Vegas. I just don't have enough information to know.
This is exactly why good government is important. The "free market" couldn't be trusted to loan responsibly, and, smart or dumb, nefarious or benevolent, these folks couldn't be trusted not to take a loan that the "free market" offered (probably even pushed on) them.