I fully agree with you that certain sections of ICANN, primarily from the registry/registrar side, may resist discouraging domain parking out of their own financial interests. However, ICANN, according to its mandate as defined by the Bylaws, is to protect the "public interest". As I understand it, this means foremost to protect the end-users' interest.
Otherwise, ICANN will become a DNS industry association and advocator, no longer to be trusted by the public.