Like I said, prove any of this. Get a geologist to analyze the moon rocks and tell you they're from the earth. Put the astronauts under hypnosis and put them on a lie detector. Do more than hypothesize.Note that the "secret" is not so much a secret any more.
Well, the issue is that they could keep it a secret for a very vey long time.
You are also making another mistake.You assume it is huge, while in reality it isn't at all!. It is all compartimentalised.
Only a few at the top know what it is all about.
Then you are talking about secrets that came out. How about those secrets that, until now, have never come out.
So, you see, your 'logic' is very very flawed.