The excuse for this is the idea that private enterprise can handle profitable units better than the state, keep prices low
Not really, the argument for state-built but privately run infrastructure is mainly one about differing goals and cashflow. Public transport may have other desirable returns other than financial ones for the state (less traffic means fewer accidents, less pollution means fewer days off sick, less traffic means more efficient business which means better tax takes, etc.). But also the state can afford to take a much longer view of the returns and issue long term bonds to finance it. Jokes like Dell's 30 year bonds are very unusual in the private sector which generally looks for returns in 2-5 years.
However, when it comes to running businesses, state companies often have a very poor record due to unclear aims and frequent political meddling. France is full of such examples (SNCF is widely considered to be a money pit). Public regulation and private provision can work quite well (Sweden and Switzerland provide examples) as long as regulators have enough power, ie. not like the rail system in the UK, which really has proved to be a gravy train for operators with no downside (Southern Rail…).
Biting the hand that feeds IT
