Aso is correct.
I was involved, in EATCHIP, APATSI. the ECAC Institutional Strategy for ATM in Europe, the ATM2000+ Strategy, the EC's Single Sky and on the SESAR Concept of Operations. In every case it was absolutely clear that the impediments were national politics, ANSP hierachies and ATCO unions. The technical problems are all surmountable but the politics are not.