A very basic and universal moral principle that every human is as important as any other. And there are very few very few basic and universal moral principles.
Now, is it true that every person has the same economic value to society? That is a very complex (and dangerous) question, but the answer is probably not. It is a very dangerous line to cross when we equate economic value with "importance".
I was reading an article the other day about how the British Health System (which provides universal health care) deals with placing a value on human life. How much to pay for treatment to the life a person? Is it worthy to spend millions to extend someone's life for 2 months? Given that there are always limited budgets, how to choose which lives to save? The system pay to save one of the eyes of the patient. Should the system spend the money to save the second eye or should it direct the resources to save another patient?