It's pure dumping. Burn an astounding amount of money on subsidising your product to undercut competitors and on advertising, then once you got the market on your hands jack up the prices.
Suppose Uber drives out literally all cab companies out of the market in some city and rises prices to absurdly high levels. Creating a brand new cab company isn’t that hard. Lease cars, create a decent app, advertise a little and you’re good to go.
Then a well-capitalized firm could suddenly leverage their scale. Order and maintain a fleet of 200,000 driverless cars, and you can get costs lower than an individual driver with his single vehicle and inefficient fleet management tools.