The trouble is that if you say "okay, we can't win Florida", then suddenly a Democratic victory becomes much harder. After Florida, the next closest state is North Carolina - and I'd expect that to be about 1.5% more Republican than Florida in 2020 still. So if you can't win Florida... what can you win?
And this is why I think it is really important people understand the next election can't just be "appeal to the Democratic base". I mean, I don't really know what the Democratic base is (or at least, what lots of you guys mean when you say the Democratic base), and I think we all have different ideas of it, but the prevailing idea seems to be the coalition of urban city liberals and ethnic minorities, especially African Americans. Well, if that's your base and what you're concerned with is winning them/mobilizing them, it doesn't win you the presidency. Almost certainly, the next Democratic president will have to get some people who voted for Trump to vote for them. I don't really see any way around that. If you sweep the Rust Belt, you win without Florida, so the Rust Belt is the place to start, but after that, Florida is clearly the next target.