if people buy housing as an investment, they take the risk any investor does, that it can go down as well as up. I don't feel a lot of sympathy for the buy-to-let guys, they're distorting the market and making it impossible for first-time buyers who actually want a place to live in rather than make a fat profit from. If there is some kind of crash, those buyers will at last be able to afford a home, which I think would be a good thing.
Personally, I bought at the top of the market 20-odd years ago and the place didn't appreciate by a penny for years. I didn't care: it was my home, not a machine to make money.