Supply is always less than demand in dense cities/countries, leaving it for the 'invisible hand' only ensures that the whole market is unaffordable and/or gentrified. Like what we are seeing in this news piece.
I don't know exactly how it works here in the Netherlands, but as far as I understand the government leases land to the constructors at its own pace, with strict quotas on social housing, to let vs to buy ratio, and free-market properties. It isn't perfect (massive bubble on the free market right now) but seems to work well enough.