I'm only a very soon to be nursing student with no connections to a hospital, hospital administration, or nursing organization, so I can't offer an insiders perspective of Hawaii's nursing situation; however, I do think the question you initially posed is quite interesting. Could the answer simply be one of supply and demand--that there are a greater number of nurses here than there are nursing jobs? Perhaps mainland nurses are attracted to Hawaii because of the wages and a romanticized version of what life is like in Hawaii, nurses from the Philippines come here to be with their families and to make a better life for themselves, and local nurses don't want to leave because of family ties and lifestyle. In addition, if nurses in Hawaii are like nurses in other states, they are working into their planned retirement years to make up for 401k losses, to support adult kids who can't find jobs or their grandchildren, to pay for their mortgage, and to survive in this crappy economy in general. To top it off, the nursing schools continue to pump out new nurses several times a year--many whom, from what I understand, cannot find jobs here. New grad nurse hiring here is dismal compared to the other 49 states...perhaps the lowest in the nation (if the statistics I have seen are an accurate representation of reality). The result of such a combination is a saturated and highly competitive nursing job market.
Regarding your comparison of employment rates in Hawaii and Florida, I would have to say that even though 6-7% unemployment seems like basically 0% unemployment to you, it is considerably worse than it was five years ago when the economy was better. At that time, unemployment was hovering between 2-3%. I remember the want ads were pretty thick at that time, and it was an employees market. However, now, the want ads have less pages than the Sunday comics in the same paper, and that ain't saying much. God help us if we ever get to 12%.
It sounds like your real question is whether or not your qualifications and experience will allow you to move here. To me, you and your wife both sound experienced. You'll never know unless you ask people who do the hiring. Maybe you could call some of the hospitals and staffing agencies to find out what it will take to get a job here. Being in the right place at the right time and knowing the right people should enable you to live your dreams. The surf is great here, by the way, but line-ups have gotten extremely crowded since I stopped hitting the water nearly ten years ago. Be prepared for a circus if you ever do make it down here. And last but not least, good luck!