And how much would it cost to build a new infrastructure? You really have no clue, do you? It takes a lot of infrastructure to launch satellites and space probes. You need payload processing facilities, booster processing facilities, launch pads, range support, and launch support services (security, weather support, etc.). All of that costs a lot of money, far more than a few days of overtime for the occasionally delayed launch. The launch site must be in a place where boosters can drop stages without hurting anyone - which usually means either water or vast unpopulated land masses. We're fresh out of vast unpopulated land masses, so until we have fully reusable boosters, we're stuck with launching over water. Coastal areas are often subject to weather problems like thunderstorms and hurricanes. To get the maximum benefit from the Earth's rotation, most orbital missions and interplanetary launches benefit from being as close to the equator as possible. Furthermore, you don't want to overfly places like Cuba for both political and range safety reasons. Where does that leave besides the Cape?