As someone else already pointed out, if the transplant from the living donor failed or had complications, now you have two people that need livers. It puts a healthy person at risk for a very low chance of a positive outcome. If they were paying out of their own pocket, then I’d say sure, go ahead, blow your own money on it, risk your own life and health. But they aren’t.
IIRC, there are ongoing experiments with organs are being grown in cloned animals; the animal is slaughtered, and the organ is harvested. Maybe someday they’ll be more readily available and renewable than they are now.
…At least for the wealthy that can afford to have farms of cloned animals.