Well the 3.5x income had been a standard for a while but recently that had increased somewhat and has been a major factor to why we are in the position we are in. However if you consider that if banks maintained a 1x income then effectively homes could only rise at the rate of inflation (I know there are a few other factors but I am keeping it simple) simply if earnings were maintained at inflation rates then house would ultimately be pegged to inflation for them to be affordable. So in order to improve the attractiveness of house buying banks have to progressively loosen the rules under which they lend so that house prices increase at rates above inflation and thus encourage more mortgage's. Increasing earning ratios, lengthening the period of the mortgage, dropping capital repayment plans etc etc. I know what you are thinking eventually there is only so much loosening banks can do to maintain this "attractiveness" of home buying, well you would be right but banks still push further until the band eventually snaps and a crash occurs and we end up where we are now going through a stage of "correction" for the cycle to rinse and repeat.
The problem is people view their home as an asset and the problem is, it is an asset but what they do not realise that its the banks asset if its mortgaged (it produces a cash flow to the bank) and at best a security if its not mortgaged. And before this gets peoples backs up claiming businesses put their premises down as a fixed asset let me explain that a fixed asset is "a fixed asset that is purchased for the objective of producing profit" You purchase your home to live in or at least you should do. Your home to you is a liability as it costs you money to own. Just like your car is a liability to you but an asset to a business on its balance sheet, just because you expect it to be worth more than you paid for something does not make it an asset.
We learn how to perform quadratic equations at school but finance, understanding fundamental home budgeting and personal balance sheets are not considered essential education for our children. Something tells me the powers that be want a nation of bad debtors.
/rant over