The HN crowd will know Adam D'Angelo (IOI Gold) - cofounder of Quora and Nikolay Durov (IOI ICPC Gold) - cofounder of Telegram. My personal examples are Singlestore (billion dollar company) which I cofounded and Near Protocol - 5Bln market cap crypto company cofoundered by Alex (ICPC Gold). There are also numerous fantastic engineers that have competitive programming under their belt working for tech primes and startups.
People who win are usually very very smart. AND they learn to work hard - you can't win without great work ethics. Skills wise you learn many algorithms and data structures cold. Plus you learn how to write small program with very few bugs from the the first try. Do they come out as complete package of a well rounded engineer - no, but there are years ahead to learn and they are trained to learn fast.
Bottom line is I can't disagree more. People familiar with the subject are often lucky to have the team and come with great network of nerd friend. Of course you will find people from this world who don't succeed, but more plenty become fantastic engineers.