I suspect that they've raised $700M because Travis Kalanick is involved. Uber made a lot of people rich, and some of those people would certainly be interested in investing w/ Travis again.
See: Wall Street in 80's.
(also interesting that the meanings are reversed in the other saying "you talk the talk but can you walk the walk?")
Tethics - Silicon Valley: https://www.youtube.com/watch?v=nfRUQh_EHoQ
Silicon Valley S06E05 - Richard vs Tethics: https://www.youtube.com/watch?v=n9cdGXa-uyM