I think ignorance also plays a part. For example, I myself thought that one of the reasons for going with a decent fund manager was access to e.g. IPOs at the discount price (+ inevitable fees) that the partner bank had access to.

If you're not able to take advantage of such things, I really don't understand the appeal.

(but then - having such large sums of money that I need help investing them would be quite a nice problem to have!)