"It simply comes down to too many people wanting to live where there's not enough space"No, I really don't think that is what it comes down to in Europe (maybe ex UK). More often than not, the reason why local authorities are planning for say 15,000 new homes instead of 30,000 new homes per year is funding not space. Not just funding for housing, but also for public transport, etc.
People in continental Europe will happily live in large appartment blocks if rents are affordable. You can easily buy a couple of single family homes in a sparsely populated area next to a big city and build 10 storeys high, or revitalize some brown field estate that is already owned by the government.
But as you correctly point out, housing in (contintental) Europe is typically subsidized, even for medium income folks. If a city is growing fast, building new homes has to be subsidized now but tax revenues are only going to come in later.
So we have three options: Raise taxes, increase government debt or deregulate to attract private investment. If you have a choice of public or private investment, which one do you choose? I think the answer depends on whether or not you know exactly how much demand there is for what type of supply and on how transparent and competent the local government is.
The demand for housing is pretty well known. We don't need much innovation in that sector. There is not a lot of uncertainty about what is required. All we need is money to build build build.
Let's look at some government bond yields: http://www.bloomberg.com/markets/rates-bonds/
And here's the Swedish 10 year: http://www.bloomberg.com/quote/GSGB10YR:IND
In my opinion, if national governments that can borrow for 1% they should take the opportunity to raise debt, tons of it, and fund housing and other infrastructures now. Or even better, introduce European infrastructure bonds to raise that money, so it can be spent in countries with higher interest rates as well.