No 'decacorn' founded after 2007 has gone public. Nearly half of the worlds tech unicorns today are private. Those unicorns that have gone public, have fared poorly. 

According to a McKinsey study, the reason behind this is that it is simply easier to stay private. The JOBS Act enables businesses to have more shareholders before going public and ample private capital (see Uber's $3.5b raise last week) means going public isn't financially necessary.

This has implications for investors, particularly those investing at later stages, or those reaching the end of their fixed lives.