Indeed.
The major problem with a conspiracy is the difficulty of keeping it a secret. Especially now, when the man who discloses the facts will become rich and famous.
I am not one to believe the CIA men of 1961-63 (CIA being shorthand for all the shadow warriors from agencies known and unknown) were Nazis, or traitors. Most of them were patriots, and courageous ones at that.
What if someone made up a story (or what if it was really true) that JFK was compromised by his sex life, or his drug taking, or who knows what, and that the failures in Cuba, and SVN, and Laos, and Tibet were the result.
What if that someone were DCI, or the FBI Director?
Do you think there would have been an impeachment, and a Senate trial? I don't.
Do you think, given the choice between a live traitor and a dead hero, that his brother would have aggresively pursued the truth? I don't.
This crime will never be solved.
That was my problem for years in making sense of the various conspiracy theories surrounding the murder. The details of what happened and how were always pretty clear and pretty undeniable. The mystery that left it all hard to swallow was the "why". The theories always presume some kind of evil cabal who wanted to destroy Camelot, and none of it ever really made any sense.
The light came on for me a few years ago, ironically after reading an aricle in George magazine. Ironic, because they published the story of the Tibetan freedom fighters, and what happened to them. It was disgusting.
I had read bits and pieces for years about them, and about the embittered CIA men whose handiwork had gone for nothing, but had never read the details until that article. The details have since been written elsewhere as well.
The army was killed to the last man, of course, with phone calls to the White House going unanswered.
About the same time I read of the wife of a CIA man who was a Kennedy mistress, who was murdered while jogging, not that that's a big issue...
Anyway, after reading the George article, a light went on in my head. I thought also about the very bitter CIA officers whose men were betrayed and killed at the Bay of Pigs, and it just hit me. What would you do? The evil cabal defending the Federal Reserve System never made sense, the evil cabal wanting to make big bucks in Viet Nam never made sense, but a coup to remove a rogue president makes perfect sense to me. This was the height of the Cold War, and it was very a deadly serious time. People weren't fooling around.
In any other country in the world, it is understood that if the president goes beyond the pale, at some point a panel of military officers will remove him. He can go quietly into exile, or he can go the hard way, but he goes.
There is no tradition of military defense of civilian institutions in our country, so exile is not an option. That leaves the hard way.
The thought you expressed that it would be hard to keep something like this secret, I have considered, and finally dismissed. The fact is that it isn't secret at all. All of the facts in the case are known. Everyone knows them. And everyone knows that if they draw the logical conclusions based on what they know, we all agree to consider them a kook. So everyone knows, but knows in silence. The case is unsolvable because we have in effect agreed that it is unsolvable. There is an interesting study in mass psychology there for anyone who wants to dig into it.
Something similar occurred when Clinton was caught taking money from Chinese intelligence. Everyone knows, everyone has agreed not to know. [The events surrounding the JFK episode were sufficiently traumatizing that no one in the security services was going to move against Clinton, or perhaps he had enough allies there to protect him from forceable removal.]
There was, of course, a long list of people who died in the few months after JFK's death, and the people who were directly complicit took their story to the grave. But it really isn't a secret what happened, just the who and why. They have, as you said, been content to let him be lionized by his biographers. It is this lionization that makes the crime inexplicable. If he was who his biographers said he was, why would anyone take him from us? But he wasn't, and the decision to remove him was probably shared out among several, including Johnson and Earl Warren. Hoover. And the "shadow warrior" chiefs.