I think the difference with those comparisons is that Uber is a massive startup, and startups have a high tendency to fail. Situations like Uber are the exact reason everyone was issuing warnings about "late stage private companies" last year. Uber might have lots cash on hand, but their unit economics makes them a ticking timebomb, meanwhile the constant PR is sending them into a huge tailspin.

Zenefits seems to have cleaned up with the departure of the former CEO. I'm not sure what their bankruptcy prospects were. Departure or not, I think Uber has challenges beyond their need to create self-driving cars (which the CEO claimed was existential for them).