I mean, there are two things here a) even Softbank doesn't assume indefinite losses/ unknown profitability, they have an exit horizon in mind that just happens

I mean, there are two things here a) even Softbank doesn't assume indefinite losses/ unknown profitability, they have an exit horizon in mind that just happens to be larger than that of most other funds, and b) a lot of tech startups that have IPO'ed in the recent past have all been unprofitable when going public, and Softbank isn't responsible for most of them. A notable exception was Zoom ( I'm talking about last year ) who were profitable before the IPO, as far as I remember.