Actually by the time full autopilot is acceptable insurance will actually go down since data will support that in full autopilot the probability of accident is lower than human driving.
Maintenance costs on an electric self driving car will actually be lower than a traditional car [1]
You are correct though that the income will have taxes applied to it.
[1] http://insideevs.com/ev-vs-ice-maintenance-the-first-100000-...