Agreed that foreign speculation is at most only part of the problem and that the drivers you mention are a large part of it, but you missed out the other significant factor in the "cultural" inclination to invest in property, which is that the favourable taxation policies (CGT discount, negative gearing, family home CGT exemption) and benefit policies (family home exemption from pension means tests) drive money into property.
In NZ's case it's even worse as there's close to no capital gains tax on any property speculation (no requirement to actually live in a property to claim it as an owner/occupier style non-investment property).