If the US is such a Wealthy country why do you need to provide insurance for so many?

The question is poorly phrased: You don't "need" to provide insurance for anybody.

The reason that not everyone has insurance in the United States is that regardless of the wealth of the country, it contains individuals who are not wealthy enough to purchse life insurance. It is analogous to "why doesn't everyone have a car" or "why doesn't everyone have a house/apartment."