Lots of people inland probably did not believe the storm would reach them in the way it did. I followed the NHC website closely, and things went down just as they said they would, but people were not listening.
Now, there are mutterings in the St Pete area that social media could have played apart with messages like 'It's never as bad as they say it will be.' The messages (if sent) were correct, Helene was worse. The storm running up the west coast on high tide really pushed up the storm surge numbers. So far Florida authorities have reported 9 drowned in areas under mandatory evacuation. Florida has only reported 11 deaths in total with none in the county that took the big hit, because people there DID heed the warnings.
However, what you must now look at is that most of the deaths were not in Florida, but in states well north of the coast. What people didn't heed in the warnings is that the forward speed of this storm would bring hurricane force winds much further inland than is the norm. It was moving at 25 mph when it hit the coast, probably twice 'normal' speed. Also, the hurricane force wind field at landfall was 120 miles across. That's big, and this windfield was still above hurricane strength probably 100 miles further inland than most expect. Remember, in most people's minds, hurricanes are a coastal thing.
The forward speed also brought a great deal more rain well inland in very a short time. Then the storm stopped. This led to a whole slew of places getting over a foot of rain in 48 hours. The Asheville area got something like 20", and hilly terrain, that only means flash floods, mudslides, undermining of highways (I-40 is toast), and waterlogged ground making it easy for the wind to tip over trees.
When those trees, mudslides, and floods hit homes and cars, you get the death toll we have.