The Treasurer Scott Morrison, in an address to the Urban Development Institute of Australia in Sydney yesterday re-stated some obvious points, acknowledging that "the challenge of not being able to access secure and affordable housing has flow on effects to so many other social and economic policy areas."Therefore, Morrison said, improving housing affordability right across the housing spectrum must be "a key policy goal for Governments at all levels, including the Commonwealth. "But he steered well away from any suggestion that negative gearing should be dismantled. "This not only would break the purchase chain on which the development of new stock depends, but undermine consumer confidence, drive up rents and weaken our banking system given the extensive exposure our banks have to the housing sector," he said.And while housing affordability has become harder for new entrants, for those who have already purchased a home, mortgage serviceability remains better than its 20-year average. Morrison, citing RBA figures, said the average buffer in mortgage offset accounts and redraw facilities had risen to around two and a half years' worth of scheduled repayments at current interest rates. "However, these buffers tend to be bigger among high income households and many households remain vulnerable to higher interest rates in the future or to changes in their employment status," he said.Further analysis shows the complex mix of factors that have seen a mismatch of supply to demand in capital cities, notably Sydney, Melbourne and Brisbane. Another factor that has supported demand for housing over the last few decades is that the average number of people living in each dwelling has declined slightly, so the demand for dwellings has grown even faster than the population.Of all the determinants of house prices in Australia, whether cyclical or structural, the most important factor behind rising prices has been the long running impediments to the supply side of the market.This not only relates to the volume of supply but also the responsiveness, flexibility, diversity and composition of that supply, as housing needs become more complex.Morrison, though, chose to take aim at slow state planning processes and approval rules, and a range of archaic laws that are still in play - if the states choose to change them.Reaction was swift. Clearly housing industry figures were grateful, while less conflicted commentators were nonplussed.For instance, as the New Daily observed, Grattan Institute CEO John Daley praised the Treasurer for telling the states to promote "urban infill" (the subdivision of inner city land) rather than simply allowing cities like Melbourne and Sydney to spill further into the fringes.But Daley then he turned to more specific points, noting "Labor's election promise to halve the CGT discount from 50 to 25 per cent would slow price growth a little, reduce distortions in the market, discourage excessive borrowing and help repair the federal budget. The Treasurer's speech is here:LINK: http://sjm.ministers.treasury.gov.au/speech/020-2016/