It's quite simple, even if you didn't grasp the analogy: the dealer ("the essay company that sold a custom written paper") is doing the renting. All the client can do is to bend over and ask when and for how long they want to rent their car (ie. resell "their" "custom written essay"). And hope it won't be happening too frequently.
but yes: If you buy a car, you can rent it out or lend it for free to whomever you wish afterwards, or even burn it, as long as you don't claim insurance on it or do it on public property.
Since you give up the title to the car to the dealer (ie. you do not own the copyright) - you cannot lend it or sell it WITHOUT the dealer's authorization. EVEN IF you designed the car (ie. did your own research). Same with essays bought from some companies - by doing business with these companies, you give up your right to OWN the essay, even after having paid a premium price for it (and doing your own research).
Again, smart students should demand that the "custom essays" and their own research work (even if it's only one sentence) should not be put up for sale without any commission to them.
If you pay a premium to rent a brand new car from the owner, it's really none of your concern that he may subsequently rent it out to others for less as a used rental car.
YOU GOT IT. So we can now agree that the term: "
BUY a custom essay" is misleading. Because, in fact, you cannot BUY a custom essay from some companies - you can
RENT it only.
Still, some not so smart students pay a premium price for renting (and some of them work for free by providing their own research). That was my initial point.