I agree with you both as regards RTI cover being a lottery that is sold on the basis of setting you to a better point than you started with. You could say it's life insurance for the car.
It's also a neat trick that the three year policy really only has to cover two years.
I maintain that the choice of taking RTI cover or not is still in part down to your personal view of risk. There are people who are happy to have the most basic insurance cover at a lower cost and have a large voluntary excess as they feel more secure.
There are however others who like to know that they have cover for everything
. They want the new car with a warranty and breakdown cover. They'll take a fully comp insurance policy with protected no-claims and uninsured loss recovery. They'll get tyre insurance and take the PPI on the finance. Basically they prefer to pay insurance rather than risk
having to pay for something unexpected. For these people something like RTI cover makes them feel warm and cosy. They'll also probably take the extended warranty on their next fridge.
I would also maintain that there can be a financial risk without RTI. Someone who is on an HP agreement, but doing galactic mileage could find themselves with a write-off that has a market value that is less than the outstanding finance.