There's no edge in entries because all entry systems are known? So, does that mean that money management systems are not known?
I'm not suggesting that entries are all there is to it by any stretch, but to conclude that money management is the only edge is silly. Because that would suggest that entries (and exits) have no value (since they hold no edge according to you). And if that is the case, then that means entries (and exits) could be randomly selected because the only thing that holds sway for you is the risk management component. Do you enter randomly? If not, then why not?
Bottom line: Both a coherent trading method and a sound and corresponding money management strategy are required.