Fact check: almost totally correct, most founded in 2009 except Airbnb which was 2007. Interesting. Seems like 2009 was a good year for startups; I guess building at the market bottom is a good way to ride the market up.
Also coincides with the start of the app + REST economy
The gig economy at least in part grew out of a giant wave of unemployment.
There were also suddenly a lot of people without a home to sleep in, and suddenly a lot of homes on the market.
Basically, right after a crash is the best time to do anything.