The cost of making government more responsive to the people who fund it and in whose name it exists should not be attributed solely to FOI, but even if it is, surely that is a cost worth bearing? Making government transparent and accountable to the public directly increases the efficiency of the public sector more than any number of government regulators or watchdogs.
Page 5. - Your Right to Know: A Citizen's Guide to the Freedom of Information Act, 2nd Edition