Economists used it to argue both for privatization and against, but always for top-down, authoritative control.
In the US, it was almost always used as an anti-"socialist" argument for privatization, by arguing that the free market would in fact be an analogue for the "natural" competition, because as we all know the Free Market always finds the most equitable and consumer-desired outcome.
I'd imagine in Europe it was more common to argue for government management.