Couldn't the launch facilities be constructed near the coast, but at higher altitude, say on top of cliffs of 50m or so?
The ideal launch site:
1) As close to the equator as possible.
2) Has open water to the *east* of the launch site. (Wasteland is also acceptable, that's what Russia does. They also care less if they drop it on somebody's head. China doesn't seem to care--we've seen them drop a rocket on a village.)
3) Has a huge amount of open space around it in case the rocket goes boom on the pad.
California fails the east requirement, it's used for polar launches (where you want water to either the north or south) but you can't insert into a normal equatorial orbit from there.
Hawaii fails the space requirement. Not to mention all the logistics hassles it would cause. Thus Florida it is and assume the infrastructure will in time be lost.