“Those relocating to Florida from the North tend to be Republican in their thinking and register Republican when they arrive.”
So, you really think that those escaping from the cesspools that their liberal voting habits have created (like New Yorkers) actually switch parties to the GOP when they arrive at their southern destination?
I really don’t think the facts back that up. Texas is a good example of this. Many Californians fleeing from the high taxes and crime that they’ve created with their leftist non-thinking have been and still are flooding into Texas and continue to vote Democrat. And it’s not just a happy coincidence for the left.
In effect, Florida's new residents tend to be those targeted by Lefties for heavy taxation in their home states. Broadly, with exceptions of course, they are culturally and politically conservative and disproportionately register and vote Republican in Florida.
Confirm this for yourself by consulting the abundant data files on the Florida Division of Elections website. Or dig into the now substantial political science literature on the subject.
California seems an outlier because the GOP has been in collapse there for decades because of the state's entrenched Leftist culture and massive Hispanic immigration. In addition, the California GOP has mostly failed to advocate conservative ideas and policies that could provide a basis for growth.