Why should the cultural sector level out when the problem is caused by external funders?

Ingrid van Frankenhuyzen's article on the high pay for some directors in the arts sector (Forget KLM and Booking: directors are big earners in the subsidised arts too.), and Wijbrand Schaap's commentary on it in the Cultural Press Agency newsletter lack context. Why do I think so? 

Salaries within cultural institutions follow collective agreements/wage guidelines established in the industries. Those collective agreements are largely public. In them, all layers ...