Because it's mostly Akp governed organization, and doesn't have much benefit.
https://www.tdbb.org.tr/?page_id=3989&lang=tr
https://www.tdbb.org.tr/?page_id=55&lang=tr
https://www.tdbb.org.tr/?page_id=4080&lang=tr
https://www.tdbb.org.tr/?page_id=4073&lang=tr