The commenter argues that a trader sitting on $409k in gains should stop active trading and park the money in QQQ, citing a cautionary example of a WSB trader who ran up to $1M and gave it all back. The mechanism is broad index compounding plus avoiding the risk of discretionary trading losses, with the author claiming this path makes the trader a millionaire in six years or less. The main risk implied is that continued active trading destroys the gains.