Many saw the Fannie/Freddie problem but were hindered from doing anything about it by democrats. President Obama was one of the folks pushing hard for banks to make the loans that caused much of our problems.
I agree with VanceMack that the housing crisis was only part of the problem - it was essentially falsely propping up the rest of the economy in lieu of real production growth. Barring imperialism, if the expense of what we use is less than what we produce and make from others we succeed. If what we use is greater than what we produce and sell to others, we will decline.