Indoor malls have fallen out of fashion in much of the country as of late, but they will always be in demand down in Florida. My dad (who lives in the Sunshine State) made the very same point that you just did when we were discussing this.
The malls in Florida and other hot climates may be the last to go, but they will go.
The vast majority of shopping will take place online in the future.
The former malls will be razed to make parking lots for the millions of UPS, FEDEX and yet-to-be-founded delivery company vans that will be necessary to move all the stuff. Also they will build massive post office box facilities, so people can have stuff delivered to a place where it is safe, dry, etc. and they can pick it up locally at their leisure.