Really stupid geology question....

It's probably hindered by the fact it would be a very very expensive megaproject.

Also the depth of Albermarle Sound might be a factor. Is it deep enough for the largest cargo ships (such as supertankers)? Does it need another megaproject consisting of a massive dredging of millions of tons of soil and debris?

Intriguing idea though.

It's because we're talking North Carolina. No one has thought of it yet.

There are several reasons. The sound isn't very deep for one, we already have Morehead City, and Wilmington as port cities to the south, and the tidewater area of Virginia to the north. Plus, the area off of the outer banks, is known as the graveyard of the Atlantic, for it's many dangerous shoals. Add to that, that the little strip of land you refer to is prime beachfront real estate, and nobody wants tankers and such interfering with their fishing and water skiing.

The reason that many of these cities are where they are isnt because of sea lanes, its because of either a needed resource or else 'power". There are natural features on the US East Coast called the "Fall zones", Heres where the rocks and higher topography of the outer Piedmont terrains, give way to the Coastal Plain.
That abrupt change in elevation cause natural water falls to exist in the drainage patterns of streams and rivers. The Fall Zones are where the colonials would locate their grain , textile, and lumber mills because they harnessed water power and here was where they got the most bang for their buck in power .
If you look at maps of all the coastal plain states, youll see that in each state, at their areas of the FAll Zones, there were hundreds, nay , thousands of old water power dams.

Skidding raw materials to mills was as important as shipping in raw materials from abroad . So, like today, transporting goods to ships was more easily accomplished by wagon over short distances between the mills and the docks than it was to create shallow draft hydraulic dams near the coasts.

Thats just a guess why the cities are where they are. The fact that, as previously stated, the Diamond Shoals and the Columbia Bar Shoals are the two deadliest stretches of water in the US make them less attractive as big seaport areas. (The whole ALbermarle and Pamlico sounds are just big swamp lined embayments like the Tidewater and Jersey SHore). Dredging is always a PITA for shallow embayments.

The state of North Carolina operates two state ports in their territory, at Morehead City and Wilmington. No other reasonable places for ports for deep water vessels exist. As FM points out, the sounds are little more than somewhat deep salt water swamps. The urban centers of the state have become the urban centers within the last 50 years. For most of the history of the state, New Bern and Wilmington were the largest population concentrations. It was only in the era of the American Civil War that this began to change. Charlotte only becomes a major urban center in the era of the Second World War. The Raleigh-Durham-Chapel Hill "Research Triangle" has become a major urban area only within the last 30 years or so as they have exploited and researched new technologies.

Set is correct about the specifric cities that gunga mentioned. Raleigh was a city specifically founded to serve as a state capital in the late 1700's. The coincidental point of the Fall Zone in this area was probably important for grinding grains. Durham was a city that was established as a grain milling center in the early 1700's. Chapel Hill was founded to act as a town serving the UNC community in the 1800's.

Really , with the exception of Durham, the other 2 didnt even seem to have any specific products that needed to get to seaports.Chapel Hill is actually "WAAAY inland" and its beyond the Triassic basin , well inland from the Falls. The cities that lie on a line from Roanoke Rapids to Fayettville are those that lie on the Falls and that does include Raleigh and Durham.

Fayettville, (named after Lafayette), was located on the FAll zone for several reasons
, The nearby mills were producing boards and grain , and the Fall Zone does identify a location where the Cape Fear River opens up to become more navigable. (It was a series of rapids and falls above Fayettville). SO getting grain to WIlmington and ultimately Charleston was a plan of action for getting ag goods down river and onto the boats.

Thanks! Like I say, it's a strange looking thing on maps...