My opinion on this differs a tad bit from yours......
I feel like a kid is more likely to fall between the cracks in a small town place like mississippi or alabama, rather than florida. there's so much exposure down there. yes, there are alot of players, but there's also alot of competition. i think coaches recruit down there so much because you can take a plane ride to ONE place and recruit forever. just take your pick of orlando, tampa or miami, that's where they all are. but, you'd do just as well to go to atlanta, houston, los angeles or dallas.
so, in essence, it isn't that the whole state of florida is some sort of fertile recruiting ground, it's just like 3 places. florida schools are going to take a bunch, then you have the rest of the sec, then you have all the schools in the northeastern side of the country coming down there for skill players too, especially those 3 big metro areas. and unlike MS, you won't find many football players outside those metro areas and select few areas in south florida, like belle glade. simply put, that's where the black population resides. and because all those coaches have to fly down there to recruit, they are damn sure going to get their money's worth.
mississippi, on the other hand, is largely ignored by everyone outside MSU and OM, because you can't just pick one place to recruit. that's why mullen's strategy is the 5 hour radius around starkville, he can afford to do that and spend some time driving, nebraska for example cannot. they have to get on a plane and go to dallas or houston. they aren't coming to mississippi/alabama to one, compete with the instate schools, and two, spend hours upon hours in a car driving from town to town.
so, in closing, those few city area, while having lots of players, get used up pretty quickly. now, if you have a tie down there, like say charlie strong/louisville to miami area, then yes you can really rope in some talented players. but most coaches probably don't like to just go in blind.