Manufacturing does pay better. However, the biggest problem with any serious manufacturing industries here is the lack of transportation routes. We are at the end of the road. There is no "spider network" of interstates, rail or aviation for that matter. It is imperative to have the ability to get raw materials, goods and product efficiently distributed. This is and always will be the restrictor for any major manufacturing here.
As was evident with the proposed mega-port in Southport, the roadways and railways would have to be seriously adjusted to acommodate the port distribution. As we all well know, all of those plans came with great scruitiny and disdain from the local NIMBY's.
Simply put, Wilmington is a strong tourist area. That's the way the people want to keep it.