Chris, where to start.
First of all, I gave you the Government's own figures. The Government wants to build thousands of new homes, and is putting tax payer money into this. That is a kind of subsidy. Social housing providers can afford to charge social rents, because of the subsidies they have already received. Social rents are possible due to subsidies. Some tenants who are not earning enough to pay their own rent, receive benefits, paid for by tax payers. The housing provider, be they a social or private provider, gets an income from the State which, in the absence of housing benefits they would not receive. This is a kind of subsidy. Do you deny these facts?
Private rents did drop. The companies I have been working for have seen drops around 10% since the recession. This is consistent with a broad range of market data, including that provided by estate agents.
If you take the total subsidy into account Chris, from all sources, the question is which is the best investment of that money? If that investment goes into the private sector, yes it will earn profits, of which a business can use to reinvest and expand the number of properties they have available to rent, and create employment. The market will punish over supply, so private landlords will have to choose carefully where to develop, to match demand. If the total subsidy is cut, it will reduce the cost to the tax payer, and shift risk into the private sector.
Charities will have to raise funds to expand the number of properties there are available to vulnerable people. If the social model creates a 'negative subsidy', then this can be used to build new homes. If charities or similar want to build more homes, they will have to become more efficient and make sure they act, I hate to say it, more like private sector landlords.