The State delivers the build of 50 units for €10m. It then leases the properties to a property management company. Because the State is not in the business of profiteering from its citizens, it only needs the return of the build cost. And because the State is not in the business of planning for retirement, the return of the build cost can be stretched out over 100,150,200 yrs plus.
So using your figures over 150yrs the State licenses the property management to a private company for a charge equal to the build cost €10m divided by say, 150(yrs) for 50units.
It works out at €111 pm. Round it up to €150 and the State will guarantee the cost of structural defects over the period.
The State could simply let out the properties to low-income tenants but its track record of managing properties is questionable at times.
So a private management companies enter a tendering process where they compete on the quality of furnishings, rent reviews, rent increases etc. Providing a minimum standard of accommodation for all lettings.
Seeing as the license fee is €150pm for each unit (compare this to a private landlord charging rent based on a 30yr mortgage of €1000pm) the scope to provide quality accommodation at affordable prices, whilst making a profit is now a real option.
The most competitive tender, based on a number factors but not least competitive rents to be charged to tenants wins.
FTB's who cannot get on the property ladder, workers who are mobile and dont require ownership, workers who are paying extortionate rents will now have a real option as where to live.