Why do you believe that? Which is to say, is this something you've worked out with numbers or is it a reflexive intuitive judgement? Because if it's the later you should recognize that your intuition is based on prices that include the labor of the person driving you which won't be included in a self driving car.

Brad Templeton did some math and thinks that self driving cars will be cheaper on a per-mile basis if you sometimes take smaller cars when you need to.

https://ideas.4brad.com/robotaxi-economics