Even if house values (or even 20% deposits) are going up faster than incomes, you can still save towards a house.
Imagine a $1MM house, with a $200K minimum deposit, $135K of household income. If that house goes up by 5% per year ($50K, $10K deposit), your income never goes up, and you save 8% or more of your income towards a down payment, you are still making headway towards the down payment. If you save 15-20% of your income, you are making substantial progress towards the down payment.
Scale the numbers up/down as you wish to fit your particular area/situation, but if the house is affordable by traditional mortgage underwriting requirements, it seems like it's possible to save for the downpayment in scenarios that I explored.
"The average length of time for a single first-time buyer to save a 15% deposit in the fourth quarter of 2016 was a whole year longer than in the fourth quarter of 2015"
I think what you've said is only true asssuming that you can always afford to increase the portion of your income that you spend on housing.
If housing prices increase faster than your income does, there will come a time when you must spend 100% of your income on housing. If prices increase further, you will be unable to pay. In practice, you will be unable to pay long before then.
Imagine a $1MM house, with a $200K minimum deposit, $135K of household income. If that house goes up by 5% per year ($50K, $10K deposit), your income never goes up, and you save 8% or more of your income towards a down payment, you are still making headway towards the down payment. If you save 15-20% of your income, you are making substantial progress towards the down payment.
Scale the numbers up/down as you wish to fit your particular area/situation, but if the house is affordable by traditional mortgage underwriting requirements, it seems like it's possible to save for the downpayment in scenarios that I explored.