The efficiency of sharing
Private property is money. There is little difference between giving away an expensive tool that's never been used and taking dollar bills and smoking them. (In market systems charity is a liability) The result, no matter how efficient for the corporation (and incredibly efficient for the owner, who gets money for doing nothing) is waste on a massive scale - but since that waste is many on the costumer's side, the idolaters don't feel any need to complain.
In a city a person, not owning a car, can walk for miles past unoccupied cars parked along the street, or unowned cars at dealerships awaiting someone with money. If those cars spend so much time unused, why did we as a society spend the monstrous cost of building them all?
True efficiency would see fewer cars is constant use, either driving or being repaired.
Imagine if instead of a few fire trucks at stations, we each had to buy our own fire truck? Imagine your house burning while your trucks down the road with a flat tire? You ask if your neighbor will lend you a fire truck, but the response is "buy your own!"? Is only the threat of death is capable of making us manage objects properly? (Maybe not - food is still considered property rather than a human right. Strangely, that's not what "right to life" people are protesting...)
For another example, think of a motorboat, kept in a garage. Once a year it is latched to the back of a car and driven at a high cost of strain and energy to a lake. There it is used once or twice over a weekend, then carried home at more cost, and left hidden away in a garage as if the effort spent to build it was all in vain.
This is literally wasteful, but is it so for the dude who owns it? The motorboat is like money in a wallet, it can be sold later at almost the same price. Overall it probably costs more to set it up for rent than to leave it in the garage as if it doesn't exist (or maybe just too much of a bother? To the starving people, masters of efficiency, with wouldn't be too troublesome! But the person who owns the motorboat has nothing to gain by letting it be managed by the starving)