You are correct, there are contributor states, and taking states, no question. However, those payments reflect all kinds of federal expenditures in states, including federal employees, projects, programs, military bases, etc. That is as much need, as it is politics.
Medicare is simply one kind of payment. It's not a matter of one state having a military base and another not. Every state has Medicare payments, but some states get paid less per recipient than others. It just reinforces the bloat.
Again, if NYC costs so much more, NYC should charge so much more.