Costs always come down with mass production. The more self-driving cars you produce, the easier it will be to bring down costs. LIDARs themselves can likely be had for cheaper if purchased in large quantities. There are also multiple companies working on less expensive solid state LIDARs.

Also, if we assume the cost of a self-driving car is 250K, that might seem like a lot, but if you amortize it over 5 years, that's 50K a year. Assuming that a car can bring in a mean profit of $10 per ride, that means it has to do 13.7 rides a day for 5 years to break even. That might seem high, but these cars are not human drivers, they don't need to sleep or take breaks, they could be on the road 20-23 hours a day, leaving some time for refueling and maintenance. I think it would be possible to bring in a profit with $250K self-driving cars and an uber-equivalent price points. It will become even easier when these cars drop to 200K, 150K and 100K, which is certain to happen once the technology spreads.