There was great resistance to national roads in the south whose leaders saw it as spending their tax dollars for northern interests. South had a large system of navigable rivers and with the Louisiana Purchase the port of New Orleans became the center of trade for the interior southern states. Similarly a system of navigable rivers flowed east from the Appalachians to the Atlantic facilitating Southern transport to the Atlantic coast.
This was exactly why Congress deemed a national road system to be a matter of necessity for the country, and later became one of the causes of the Civil War that doesn't get much attention.
There was no way in hell the U.S. government was ever going to allow a scenario where a loose confederation of sovereign states allowed state governments to control access to the entire Mississippi River system. Check out a map of North America to see how large this watershed is.
Interestingly, evidence of this mindset prevails even to this day. The Army Corps of Engineers is tasked with the maintenance and upkeep of the locks and dams along most of our internal navigable rivers (the Erie Canal is a rare exception, as it was constructed within New York's borders for the purpose of keeping it under state jurisdiction). One of the absolutely non-negotiable terms of that federal jurisdiction of these waterways is that they must always be open to every user -- commercial and recreational vessels alike -- at no charge.
That sentiment still exists today.. People have said that Virginia shouldn’t spend money to upgrade I-81 because too many vehicles from other states use that road.
Of course, this is the same Virginia that has no problem taking Federal $$$ for roads rather than spend state dollars for them.