It’s true insurance companies need to take in adequate premiums in order to have the money the money to pay claims. And when done in balance, insurance is a great thing. Not all insurance in a scam, no doubting that.
But the current state of insurance, especially health insurance in the US, shows that these companies are making massive profits. How does this happen? Literally one way: They take in more premiums than they pay out in coverage. How? By either knowingly overcharging people or skirting out of paying covered claims through other means (such as baseless rejections).
That’s the problem with the entire insurance industry and why it must be properly regulated in any industry: It is a race to the bottom. The worse the insurer treats the people that buy insurance from them, the better the company does financially (charge a lot, pay out a little). Mix in the fact that (1) you cannot shop around at the time you need a claim and (2) the contracts are so intensive only a sophisticated legal team can interpret them, and it’s a recipe for disaster.
So you’re right that all insurance isn’t necessarily a scam. But if you can’t see that the US health insurance industry raking in profits shows serious dysfunction that could be considered a scam, it’s worth taking a second look.