Risk invariably ends up in the public realm. The City of Hamilton got out of private operation of their waste water treatment system. In 10 years the consortium changed ownership three times, then they walked away. Hamilton city council can't walk away from providing water treatment services, so who is left holding the bag? It is the citizens of the city of Hamilton.
This is not to say there isn't a proper, historic, completely appropriate role for the private sector to make a profit building infrastructure. Mortgaging debt is never a good thing. Surely to God we have learned that, as a people.
Senior levels shouldn't be prescribing to junior levels of government how they should operate their public businesses.