Yes, Airbnb, WhatsApp, Venmo, Groupon, Instagram,Uber, Pinterest, Slack, Square, and a whole bunch of other companies started in the 2007-2010 recession.
But the real reason was this.
On the July 10th , 2008 Apple launched the App Store.
Smartphones had just become mainstream, 3G coverage and tariffs were popular, we now had phones we took everywhere, with cameras attached, GPS chips in them, and our behaviors shifted.
The fact no mobile centric companies had existed before, the fact broadband streaming was now so prevalent for the first time, created the perfect conditions to launch something that had few barriers to take up.
We had phones with blank space on the home page.
Many successful companies launched well before and rocketed to popularity in this time, GrubHub, Google, Match, Google Maps.
Think of the last new app you downloaded and kept? Things now generally have to replace something we have already.
Don't get me wrong, now is amazing time to launch a company, but the product has to be a little bit remarkable. Or leverage the power of a whole new environment thats new.