This is true, but incomplete. Such unsophisticated investor has to control his frequency of trading, and also the frequency of trading of his etf or mutual fund

This is true, but incomplete. Such unsophisticated investor has to control his frequency of trading, and also the frequency of trading of his etf or mutual fund. Any fund needs to do trading, re balancing, etc. So there's a double layer where ppl get charged 'the vig'.