Real Estate Businesses ASX

With everyone talking about the impending doom of real estate in Australia I wanted to get a better understanding why not just short real estate directly? I understand Atayls and a few others have puts on big banks for increasing mortgage defaults, I was wondering what everyone's thoughts are on the big real estate mongrels like GMG or SCG? They seem like prime candidates if house prices start decreasing in value, they will make less compensation revenue hence less profits. GMG has the bonus plus of increasing insider selling from their board of directors.

Anyways, if anyone has any interesting reasons why this wouldn't be a great opportunity I would love to hear.

Cheers,