Proxy Advisers - cosy and intransparent cartel

Who gives the handful of proxy advisers to right to set their own 'policies'?
Do they ever ask the real end investor, - and not only the intermediaries that pay hefty fees with other peoples' money?
Why does it seem impossible for real end investors - and the public at large - to find out the fees that are paid to proxy firms so that they can do the work that the financial intermediaries should be doing, i.e. supervising the companies they invest in on behalf of the great unwashed public?
(10-Feb-2019)
ISS Policies on Compensation