These investors aren't investing their money, but someone else's money. If Uber folds now, these investors are to blame. But if Uber folds when the great crash (a-la 2001 and 2008), then, well, it's the entire economy - not the individual investor's fault.
So they do whatever is needed to keep Uber with high book value until the big crash. What's $20B of other people's money to maintain your sterling reputation as a smart investor?
> [VCs] get paid to allocate other people’s (LPs) money, and they are smart enough to transfer the risk. For example, VCs habitually invest in one another’s companies during later rounds, bidding up rounds to valuations that allow for generous markups on their funds' performance. These markups, and the paper returns that they suggest, allow VCs to raise subsequent, larger funds, and to enjoy the management fees that those funds generate.
And he has more such analysis. It's quite a good read if you are interested in that stuff https://s3-us-west-2.amazonaws.com/socialcapital-annual-lett...
How much does Cruise or Waymo burn per quarter? That might give us an idea of the ATG part. How much does Convoy burn? That might give us the Freight parts. No clue how we might estimate Elevate and Eats.
That said, it's worth looking at how Amazon is doing overseas these days:
https://www.fool.com/investing/2018/03/19/why-amazon-is-stil...
This is why growth abroad matters:
https://www.gapminder.org/fw/income-mountains/
Everyone bloviating with their personal ridesharing anecdotes is missing the bigger picture.