Because value is relative to other valued things.
Resources are limited, so what you spend on "essential services" cannot be spent on other things.
Healthcare is "essential", but if you spend 100% of resources in healthcare, it will never be enough. You can spend billions to keep alive a person more minutes, and he will die anyways, but society would lose all housing, all food, all clothing, and would be miserable, so healthcare doesn't had infinite value.
If you find any "essential services" too expensive, is because you need other things more important, like having food or a house.
If the state pays for "free" healthcare, it has no limit to spending, and you cannot more get a house, food, clothing, or anything else.
That's why "essential services" have a price, like anything else, and should be restricted to be profitable.
Profit means that the value produced is higher than the cost, because the cost are other things that you need more.