Because the big ones are signed up with the main companies, and the smaller ones do not want to be swamped by calls from every Tom, James, Dick and Linda from every small funder out there. And if I have some good ISO's working with me, why in God's name would I actually post that?!?! Its an open invite for someone else to try and grab their business...

I am sorry, but this has to be one of the least thought out questions ever posted here.