Uber runs out of cash next year if they don't. If Softbank puts money in, it will probably be on terms very favorable to Softbank.
Uber's funding rounds: [1] The "undisclosed amount" round in 2017 was reportedly not big enough to change the fundamentals.
[1] https://www.crunchbase.com/organization/uber/funding-rounds
According to this (Link: https://www.nytimes.com/2017/05/31/technology/uber-limits-lo...)
Uber has $7.2B sitting in the bank, with losses reducing ($708M) in the first 3 months of 2017. I'm sure they can get profitable or break-even in that time.
There are several ways this could play out. One possibility is that if Uber raises their rates, people will mass-migrate to Lyft. Whoever survives that war of attrition may monopolize the space.