The market is artificially biased towards investment rather than owner-occupier through economic incentives such as negative gearing, tax breaks and the accumulation and unequal distribution of wealth. Viewing it as supply and demand is simplistic and ignores the synergies that can be enabled through structures such as housing co-ops, land sharing and community sustainability plans. I dont think the banks are the easiest targets in this instance since there is no financial incentive to divest from unethical property investment, as there is with fossil fuels.