Yes, and if you want to advance the argument that finance is too well-regulated for anyone to ever break that separation, no matter what the incentive, that would be a great contribution to the discussion!

But that's not what the original comment[1] was doing. It was just saying, the roles are nominally separate, therefore there can't be collusion, which is a hasty inference I was right to call out. I completely agree that a different argument, one not made in the comment I was replying to, might not be so bad!

[1] https://news.ycombinator.com/item?id=35956915