> You pay health insurance so you don't have to pay the full cost later on.
When you buy health insurance you pay more than the expected value of the full cost, both as a result of the cost of providing the insurance and the over-consumption as a result of insurance making patients price insensitive.
The reason you buy insurance is in case your medical bills are more than average and you can't afford them. For the average person the insurance is a net loss but the cost savings of not having it aren't worth the risk.
> And it could easily be that the shipping cost + taxes generally means that the system stays afloat.
If the system is worth more than it costs then it will be able to charge prices that allow it to stay afloat. We generally don't need systems that cost more than they're worth.
> And besides, if you tax correctly, it wouldn't be the same rate for everyone (income taxes should be higher for those making more, for example) nor would it be more than the flat shipping costs so long as the tax money actually went to the postal service.
Everybody always wants somebody else to pay for it. But it's the people in the middle and not at the top who actually pay for stuff, because they're the only ones numerous enough to do it.
> In both cases, are the employees getting paid fair wages?
That sounds like a question for the employees and not the customers. Naturally if they're getting paid below market rates they should consider seeking other employment.
> Does the tax mean I'm not getting charged for receiving packages?
You can already get charged for receiving packages. It's called COD. Nobody really uses it because it's much more convenient to charge up front than have the carrier try to collect payment from the recipient.