Why don't publishers cut CPA companies out of the deal?

Here's a question I have directly for an affiliate.

Why don't affiliates simply go directly to advertisers instead of the CPA networks and cut deals with them for sending them traffic? Or, do they do this already?

Here's the reason I ask. I have an acquaintance who has worked inside of 2 of the largest CPA companies. He has told me that there is a well known term called the Scrub. Basically, this is a term used to describe the profits that CPA companies essentially steal from their publishers. He told me that all CPA companies will take more than their agreed share of the profits, and it is always the affiliate that loses, not the CPA company, and not the advertiser.

I have not verified what he has told me...but....he had no reason to lie to me. Ya know...nothing to gain from it.

Anyway, I figure, even if a CPA company does not steal profits from their publishers, they still cut into the profits of both the advertiser and the affiliate. Nobody can argue with this.

I realize there must be many obvious reasons why Top Super affiliates like Rosalind & Zac Johnson would still go to the CPA networks, I just would like to fully understand why?

I figure they could cut much better deals for themselves if they went straight to the advertisers.

Currently I'm working on a project that I hope and predict will attract the super affiliates. I believe this will be the case, simply because it looks like I'll be able to offer them a higher payout for their efforts than anywhere else I have seen.

All replies are welcome.

Thx kindly
Gary Roblin