The same was said for Paypal, Amazon, Facebook and Google.... These ventures don't plan on being profitable early on.
The problem with Uber is that the business model is too easy to replicate. For under $100k you can set up a website with an app. The vast bulk of the ridership are people who live in that city, so the barrier to entry is an ad campaign in one city. The only advantage they had was their willingness to brazenly ignore the law and break the taxi monopoly -- but now that the monopolies have been broken and the laws eased up, anyone can benefit from that advantage.
Their only hope is developing self-driving cars.
A financial services company like Paypal requires a lot of trust on sides -- and PayPal particularly requires two parties who don't trust each other to both trust a third party -- so it's hard to set up a competing service.
Amazon has huge efficiencies of scale, so it's hard to set up a new one (but Alibaba did).
Facebook is one of many of the same thing; there's a natural monopoly in social media, but it could be broken in a year if a new cool social media app comes out.
Google had technology that was hard to replicate, and used that to spread into other domains before the technology became obsolete.