The President is the chief executive of both agencies. He didn't need to have one agency recommend it to the other for consideration over a multi-year timescale. It could have been executed within a few weeks to a few months. The office of the President knowingly chose a prolonged approach.

I feel it is misleading to call it an "effort", as if the President was struggling against the very agencies that he was elected to lead, decisively. Congress is supposed to be the slow-moving deliberative rule-making body.

If he really did struggle, it would say a lot about the growth of the administrative state and would highlight a constitutional health issue.