very simplistic point of view - you're making the...

very simplistic point of view - you're making the assumption that management individually have enough free cash flow to be able to buy an abundance of shares at their leisure. Also if you're management with a few hundred thousand - few million in shares or rights already, It doesn't make a lot of sense from a portfolio risk perspective to buy more. Finally, while it may be easy for management to buy shares on market, it's typically much more difficult to dispose of those shares as theirs usually something in a contract that will restrict disposal. That restriction can last for a period AFTER management has left, you need to be willing to tie up cash for that period.