I wonder if that's because the weasels and mink had other food to eat.They are there, you just haven't seen them. Florida has 3 species of mustelids of which the long-tailed weasel and American mink are of concern. Florida has always been in their native range.
Long-tailed Weasel - Mustela frenata - NatureWorks (nhpbs.org)
Weasel and Mink Sightings (myfwc.com)
I hadn't seen mink where I live for over 60 years, then in the course of a week, mink massacred $4,000 worth of my chickens.
I lived for 13 years in a water area..near a river...creeks surrounding me in every direction but I never saw a weasel. Never saw a rat either, so maybe the rats were keeping the weasels busy.