Why are houses today so expensive?

Question

It seems that back in the 70's a house could be bought for around $17,000.00 now they're in the range of $100,000.00 or more. 

Why are they so expensive?

1970
Median U.S. home price: $17,000
Median household income: $9,300

2009
Median U.S. home price: $178,600
Median household income: $50,200

Answer 1

Houses are bigger today.

Everything is more expensive. People make too much money.  

There are far more people today than even in the 70s. Simple supply and demand means that the more people we have, the higher prices will generally be.