That might be because the size of the agency has to do with the number and difficulty of the tasks that need to be done rather than the size of the private sector involved.

Also because agriculture is a fucking strategic industry. People can’t eat shitty electric cars or reusable rockets. If the US “efficiencies” itself into a famine it would be an extremely funny tragedy, mostly because of the irony of “gommulism is when no food” arguments.