A very valid point Nubian
If people want the experience enough, they will pay the extra costs.
Indeed, however there would be far fewer of them and the demand would unlikely meet what would be required to run a successful business.
A near 2x increase in tourist flight costs would not be good. Most already consider a scenic flight to be a huge luxury.
The issues here transcend the number of engines, the flight being quite surviveable with just one as the surviving pilot clearly demonstrates.