Unicorns between 1997 and 2019 include many patently unsustainable businesses whise valuation was total froth, and whose investors lost enormous amounts of money. I'm not sure this was a sign of anything other than participating in a feast of capital.
~44% of unicorn founders identify as immigrants.
The "nearly half" number probably sounds surprising to many, but if you put it in context of how many immigrant workers there are in the US - then (I'm guessing) it will be a lot less surprising to many.