1) Humans suck at keeping their mouths shut

2) Most conspiracy theories posit excessive competence (itself extremely rare) that somehow defies all the weird things that reality can throw at you and make things fail.

Most "conspiracies" had plenty of evidence even at the time--people chose to ignore it because it benefited them. See: Epstein, Weinstein, Cosby, etc.

So, real conspiracies that people don't know about do exist--but they are tremendously rare.

Can you prove these aren't just crackpot theories? Do you have any primary sources or tangible evidence to support your claims?