One thing has definitely changed from the 70's BIG TIME.
I can clearly remember (eg.West of Brisbane), but I am sure it is other places also including where I am now in Tassie and also Vic where I have some property - anyway, you used to pay eg. $7k for a bit of land and then you would put a house on it for about $20 to $30k (depending on fit) this example is from the west of bris. area.
Now - the land costs much more than the house in a lot of areas.