What difference does the population make other than that at 330 million economies of scale might appear that aren't significant at 5.6 million?

According to this website [0] there are 30 states with a population of less than 6 millions. Why can't they each operate like Singapore?

[0] https://worldpopulationreview.com/states

The problem is that states are like accidents of history and are fairly arbitrary.

You need this with lots of stuff. “Vice” states are adjacent to more prudish states. Think New Hampshire, Delaware, Pennsylvania, South Carolina.

In the case of healthcare, states tend to push costs to somewhere else. As in send the sick person to NYC.

Singapore's area is 283 square miles. Rhode Island is the smallest state, and it has an area of 1214 square miles. Four times larger, with people throughout needing care. That alone will add a fair amount of cost.

Granted, not the total amount spent, but city states do have some advantages on things like this.

Perhaps on a state level?