Here's an example of a real, widespread conspiracy for you. There was a certain case that I did research for back when I was a legal researcher/paralegal for a medical liability/mass tort firm. It was a medication that was supposed to prevent heart attacks and control diabetes.
Turns out that what it really did was cause herst attacks and make diabetes worse. Imagine that. Thing was, they knew about this pretty early on. You see, they can do as many studies as they like privately until they get some that look good. Then use those to get approval.
In addition to that, they have basically pet doctors who are willing to lie. These doctors organize conferences where they shill the medication. Real nice ones with five star dinners and shit. And there were even straight up payoffs and sexual favors by pharma rep girls.
All of this stuff started getting exposed within the case, so they did a mass settlement, which is why you don't know about it. There are even companies that will run studies for drug companies whose advertising srrategy is "our studies will get the results that YOU WANT!"
It was all very disgusting. And I was underpaid and I hated it but shit it was eye opening. Every company does this. There is also a revolving door between people high up in pharma firms and people high up in regulatory agencies. Its a literal, true, widespread conspiracy.
Interesting that people really belive that any suspicion of conspiracy is pathological. Yet, anyone that's worked in plaintiff side law (pharma liability for me) has seen conspiracy after conspiracy unfold in documents and in depositions. Payoff, lies, bribes. It happens all day.
The manhattan project involved tons of people, was the single largest use of electricity in the country at the time, and was kept so secret that even the white house didn't know about it. Powerful people with the means to do so will work in secret for their own interests.
Northwoods, mockingbird, mkultra, paperclip, all real, widespread, and admitted by the people who did it. People today belive that this all stopped for no reason. The idea that suspicion of conspiracies is inherently pathological is something that is very useful to power.