I feel like Airbnb and Uber are both large and popular enough, at this point, to push regulation in the direction they see fit. Anyone standing in their path will be labeled protector of the old monopolies and anti-consumer.
To me, its clear there is a non-zero risk that both businesses could get squeezed by regulation - the investors are betting that there won't be an impact from regulation or that the cost of following the regulation will be worth it (which you'd expect if you've got the scale to follow through).
Factor in my girlfriend and our household is at around $20k.
If Google can charge me $10k-$15k annually to not own a car but be able to have it available all the time? What's $10k * 137,000,000? [1] At those levels, the failed Uber experiment can be a whimsical write-off. Or perhaps it's a strategic venture to handle some of these pesky regulations we're always talking about Uber fighting.
I don't want to own a car. I just want to have the freedom to be mobile at a moments notice.