The name of our country is the United States. The state was intended as the primary unit of general government.
Lots of land is outside of cities, and that can't be left ungoverned. And many counties have very few people, which make a lot of government functions impractical or insufficient.
So states are still a reasonable unit after 250 years.
Alternatively the name of our country (well my former country but whatever) is the United States because existing colonial governments held significant power and weren't willing to unite if it meant they could be unseated from their cushy political appointments.
I don't think going by names is the best approach when we've got legal documents and statements to go by which are far less vague.
Lots of land is outside of cities, and that can't be left ungoverned. And many counties have very few people, which make a lot of government functions impractical or insufficient.
So states are still a reasonable unit after 250 years.