I think a level 5 car business is likely to be a poor way to make money.

In such a system your car is just a commodity, and people will take the cheapest option of similar condition. In such a system, there will be many people who own a car, but are so desperate for cash that they will rent their vehicle for less than what it costs to operate it.

They will sell a ride that costs them a $1 for $0.50 just to get their hands on that $0.50 now, even though it screws themselves over in the future.

Plus you will be competing with people who can buy the cars at a more lower price than use -- such as the car manufactures themselves, dealers, or taxi companies buying huge fleets of vehicles. So their cost of operation will be lower, meaning they can still turn a small profit while you'd be taking a lose.

Level 3 is basically here this year -- though barely. Mercedes is shipping level 3 this year, but it is only enabled for speeds under 37 mph and some select stretches of highway.

I think Level 3 to 4 will happen pretty quick. Level 4 to Level 5 could take quite a bit of time. But I think many human drivers have not reach Level 5 yet.

Level 4 is pretty darn useful though. A Level 4 vehicle may not have a steering wheel and pedals.

Level 5 is almost an impossible standard. Instead level 4 cars will just get more and more capable. What does level 5 even really mean? Must the car be able to go offroading and rock crawling with ease? Many humans can't even do that well.