It's very bizarre I-95 doesn't go through Charleston and Myrtle Beach. Is that because of the difficulty of building in wetlands?
I would say it's because of general anti-South bias as well as the fact that Charleston and especially MB are a lot less important than the larger cities that I-95 needs to serve such as Washington DC and the Florida coast, so I-95 simply goes relatively straight from Washington/Richmond toward Savannah/Florida.
But Charleston and MB are clearly more important cities than Florence
I-95 mostly follows US 301 from Petersburg, VA south to Santee, SC (once it’s across Lake Marion), then works it’s way to eventually follow US 17 towards the general direction of Savannah, and to get back closer to the coast.
Way back before I-95 even existed, US 301 was a very important route heading south. Probably more or equally as important as US 1.