Don't put much faith in the "next generation" being the Democratic salvation in Florida. Since the 40s a large majority of Floridians have been born out of state and moved here; right now only 36% of Floridians were born in Florida and I expect that number to stay low in the future. How the younger generation being born here votes matters much less than the ideological make-up of the people who move here. Throwing those people into the equation makes it much more difficult to say there's some sort of demographic destiny for us.
But the people who move to Florida, tending to be old, have many fewer kids in Florida than do people who do not live in Florida. For a while, the olds who move to Florida dominate the electorate, because they are old and turn out to vote at higher rates. But eventually the former youngs (tending to be minorities) grow older and begin to vote at higher rates as well. That's basically what is happening now. It is not just a matter of the younger generation. It is just as much a matter of the fact that, increasingly, the older generation (and middle aged generation) is less monolithically made up of old whites who moved to Florida (and old Cubans who fled to Florida) and are inclined to vote Republican.
For example, it's not just that the new 18-29s are more heavily non-white than ever, and that non-whites are increasingly uniformly hostile to Republicans. It's also that the 18-29s who voted for Obama starting in 2008 are now 8 years older, and will vote at proportionally higher rates.
