@kolev @AlexanderKingsbury Some do, some don't, it really depends on the libertarian - it's a very broad school of thought.
Some businesses, if privatised, would run more efficiently, but as you point out that can run into problems. So you might, for example, privatise electricity delivery, but have government oversight to ensure certain levels of performance or delivery, in theory getting the benefits of both. Or not, it's complicated.