obviously the least price-sensitive 5% would remain. it's not like they're running currency exchange or something - people don't have a super set demand curve. maybe 95% of their customers do, but not 100% of their customers... (unlike a currency exchange, for example, which would drop to precisely 0 users worldwide if it increased prices by just 10%, since 100% of any such users are super price-sensitive. likewise if a currency exchange subsidized exchanges by 10% it would have more users the next day - by far - than people on Earth. easily a trillion "users", or whatever the rate limit is for signing up and performing exchanges. try to visualize these two different demand curves and you will see that Uber should still have some users if they raise their prices, because not all of them are completely price sensitive and only use it because it subsidizes rides, and not for any brand or convenience reasons. unlike a commodity currency exchange which exists under ironclad demand curves that drop to 0 if you move along it even slightly. picture these curves.)
Can you provide a source for this? I'm honestly very curious. I've seen this claim bandied about for years, but I've never seen a source that verifies it. Is Uber really losing money on a marginal basis in developed markets?
Here's an article with citations from November of last year. Note that it does use data from 2015, since at the time that was the most recent publicly-available published data.
Their profitability problem isn't just one of opex. They don't have margin, either.