>> The cost of failing to hire a good engineer is small
I'm not so sure about that.
https://en.wikipedia.org/wiki/Jan_Koum
"In September 2007 Koum and Acton left Yahoo and took a year off, traveling around South America and playing ultimate frisbee. Both applied, and failed, to work at Facebook."
"On February 9, 2014 Zuckerberg asked Koum to have dinner at his home, and formally proposed Koum a deal to join the Facebook board - 10 days later Facebook announced it was acquiring WhatsApp for US$19 Billion USD."