Of course, people don't buy homes to invest money. They buy it to have a nice place to live.
That's true, but you can live in a rented home too. And if you need to move, you can always move without worrying about losing tens of thousands of dollars.
Actually, that's not true. People buy houses, fix them up, and sell them for profit all the time. It's called house flipping.
And that flipping crap plus letting any schmuck get a loan helped prices go up faster than they should have, making the crap loans seem great, making it easier to do more flipping, driving up prices even faster, etc., etc., until it all fell apart. You could tell it was going on by all the houses having for sale signs go up only a few months after they came down.
I was looking at houses about 10 years ago, was finally making enough to afford something. In less than a year all of the ones I was looking at went way out of my price range, in just a few years they all went almost triple what they were when I first started looking.