Possibly no one, not even the ET had the big picture. It is not prudent to launch a massive attact when you have only a vague and varried idea of who you are fighting, why you are fighting and what resources the alleged enemy has?
I think the usual accounts make good sense. Deny that anything is happening and gather more information. Unfortunately official denial means you miss out on a lot of opportunities to gather information. It also means the various agencies come to a wide variety of tentative conclusions, which make decisions career risky.
Much the same happens with independent researchers who are typically short on money so the temptation is make money selling books that suggest far out hypothesis. Neil