Let's guess driving that much that takes about 2 years[2]--if you assume a conservative 1 technician per 50 vehicles[3] to maintain these you also have 2% of their salary * 2 years (say another $3K). Throw in another $1000 for tabs etc, $1500 for the labor for a couple hundred car washes[4], $1000+ for losses related to crashes[5], $500 for parts and maintenance[6] and we're easily at another $7K+ in costs that have to come out of Uber's existing share.
[1] https://therideshareguy.com/how-to-calculate-per-mile-earnin... (This is for a 43MPG Prius, with ~$0.06/mile of depreciation. I exclude the depreciation for the calculation above, but need to add back in a similar amount for the difference in MPG.)
[2] https://bizfluent.com/info-8446407-many-cab-driver-drive-yea... Estimates of how many miles per year a single taxi gets driven range here from ~40,000 to ~90,000, so 75K/year seems plausible for a fully autonomous vehicle.
[3] http://www.government-fleet.com/channel/maintenance/article/... (This seems very conservative to me, consider for example that Hertz has about 1 employee per 13 cars.)
[4] https://uberpeople.net/threads/how-often-do-you-have-to-wash...
[5] Estimated from average of 1 claim per 18 years per driver and $7500 in cost per accident https://www.forbes.com/sites/moneybuilder/2011/07/27/how-man... http://www.tavss.com/library/va-nc-lawyer-economic-and-compr...