The economy was doing a fine job of self-correcting & adjusting until a) The federal housing "fix" hit; and b) the government starting trying to "help".
See, the beauty of a capitalist system is that it takes care of itself. Yes, there will be recessions, but they don't turn into depressions unless someone does something to exacerbate the situation.
In the 1930s it was a combo of a natural recession, the dust bowl & the lack of able bodied men (since so many of them had died in WWI).
Now it's a combo of a natural recession, Fannie May, & the Stimulus Bill.