> I agree, and that's why I don't like using the word insurance when it's not really insurance in the conventional sense.

Once again: that might not how it works in the US, but the US is not the world and hence irrelevant for the _general_ concept of insurability for healthcare. If you only want to talk specifically about how it is _right now_ and _only in the US_ then I agree with your sentiment.

I'm just answering to your post because I have the impression that you are making very general statements.

> What I mean by insurable and uninsurable is that an entity can come in and sell insurance which can benefit the buyer alone, and is not an explicit subsidy to the other insureds in the risk pool.

That's how it works though, maybe not in the US but for example in Germany.

> However, for health, it's a no brainer to opt out of health insurance between ages 20 and 40 (maybe not if you're a woman that's going to have kids). This makes the risk pool completely full of people experiencing losses and that point, it's just a cost sharing arrangement.

If by "no brainer" you mean that some or many young people "don't think" and do something irrational, then yeah.

Someone who thinks about it and makes an informed decision will _not_ opt out when they are young. There are two reasons:
1.) Even when you are young, you can get cancer, HIV or other chronic and expensive diseases that exceed your savings by far.
2.) Even if you can pay your diseases out of your pocket, you might get a disease that is cheap when you are young but will cost much more when you get older. If so, you won't be able to pay the price of insurance anymore when you are older. However, insurers can (and do, maybe not in the US) offer contracts where they cannot cancel the contract from their sides just because you get sick or more expensive - however, therefore the premiums are higher (even when young) so that they can cover the costs that statistically will happen. Essentially, if you are young and stay healthy until you die, you will have paid all your life long for the people of your approximate age that also were healthy in their youth but became sick when they got older.

As for your point about calling it a tax in the US:

> I think we'd be better off if we referred to this as a tax and recognize that the increase in insurance premiums is going towards benefiting others by giving them access to previously inaccessible healthcare.

I think both the current and your proposed solution are not optimal.
IMGO the right approach is to apply separation of concerns:
1.) Decide for a standardized "minimum" that any insurer can offer and get certified for their plans if they fulfill the criteria
2.) Make this minimum standard mandatory for everyone, but allow for the choice of which exact plan and insurer to choose
3.) Let premiums be premiums which everyone pays to the insurer
4.) If someone can prove they cannot pay, they get supported by the state so that they can pay for a minimum plan (otherwise it can't be mandatory obviously)
5.) Whoever wants to have better insurance can get a plan that covers the minimum + more stuff

Now there is clear distinction between premiums and tax which is used to pay for people who cannot afford health insurance.

Oh, also, the US could stop this strange way of pretty much tying insurance to employer. I never understood how this could happen.