As I have also set out, without that huge rise in existing house prices, there would, also, have been no rise in new house prices, because, as with every other commodity, over time, rises in social-productivity leads to falling unit values. The process with houses is that set out by Marx, in relation to average industrial profit and rent. The large majority of property transactions – around 70% - are in relation to existing houses. It is the price of these houses, therefore, that determines the market price of all similar, new houses. Suppose, the cost of building a house, of a given type, breaks down as follows. Materials and wear and tear of equipment used in construction £10,000; Wages £5,000; Profit £6,000. Suppose the average industrial rate of profit is 33.3%, so that, the builder makes a surplus profit of £1,000, and this is rent appropriated by the landowner, here, capitalised as a one-off payment forming a capitalised rent/price of the land.
In this case, the house sells for £21,000. The land price accounts for >5% of the price. Now, suppose that speculation drives up existing house prices, which, as noted, determine the market price of all new, similar houses. In the 1980's, we noted that, in Britain, as a result of such speculation, house prices quadrupled. So, existing houses of this type, would now be selling for say £90,000. Even if we assume no change in social productivity, so that the values of materials, equipment, and labour-power do not fall, as, in reality, they would, the builders clearly have a huge incentive to build, because, now, the cost of building is £15,000, whilst the house sells for £90,000, giving a profit of £75,000, as against the average industrial profit of £5,000, a surplus profit, now, of £70,000, as against £1,000, previously. The builder, however, cannot build, unless they have land to build on, and so, the landowner, now appropriates this £70,000 of surplus profit as capitalised rent, in the price of the land. Its not higher land prices that lead to higher house prices, but higher house prices that lead to higher land prices, just as higher surplus profits lead to higher rents.
For the capitalist builder, the incentive to build, becomes severely dented, once this process results in all of their surplus profit being appropriated by landowners, in the form of higher rents/land prices.. In their calculation, they see that, now, before they can build any houses, they must lay out this hugely inflated price of land to the landowner. Economically, as Marx describes, rent is not a cost of production, just as interest and taxes are not a cost of production, they are all deductions from industrial profit/surplus value. But, the capitalist does not see it that way. The builder, sees that, they could sell a house of the given type at a current market price of £90,000, but, now, must first lay out, £70,000 to buy the land. They must lay-out a further £15,000 for the construction of the house, leaving them with a profit of £5,000. Instead of seeing this in terms of making the average industrial profit of £5,000, on the productive-capital they lay-out (£15,000), the builder looks at having laid out, £85,000, in order to get a profit of just £5,000. As Marx noted, this is the pernicious role that rent plays in holding back production.
This also explains why so many builders sought to keep down the selling price of the houses they built, by not buying the land, and so selling houses, leasehold rather than freehold. The attempts, now, to limit the amounts that can be charged, each year, for leasehold properties, will only further deter, new house-building on that basis.
Using potential money-capital to build new houses, rather than using it to just bid up the price of existing houses, by inflating speculative, monetary demand, would, also, have employed more construction workers, increased demand for bricks, cement and so on, as well as for workers in those industries. In short, the liquidity that central banks injected to inflate asset prices that had crashed, as bubbles burst, starting in 1987, would have flowed into real economic activity, and would, then, have led to higher commodity prices, rather than higher asset prices. The major caveat to that, of course, is that, the use of this money, as money-capital to increase supply of commodities, does not lead to a rise in their price, if the increase in their supply, is at least equal to the increase in the quantity of currency/credit thrown into circulation, as Marx sets out in A Contribution To The Critique of Political Economy.