Questionable analysis because it does not take into account the many founder-led companies or the many hired CEO-led companies that fail altogether, that never get acquired and never reach a $1 billion valuation. We do not know if hired CEOs are under- or over-represented among the 27% of unicorns that had hired CEOs without knowing that information, nor do we know the statistical significance of this sample.

This is a case of confirmation bias. You make brief mention of that, but it basically means that this is all opinion and not actual data-derived information.