I just don’t think people pay Disney prices to see animals that live near them and/or are visible at the local zoo. The local zoo may also have a lion or an elephant but Disney has an impressive assortment of animals that most WDW guests find exotic.
Also, it’s hard to pull off multiple biomes with the way DAK lands are themed. Asia could include Siberia for some variety, too, but they stay tropical except for the peak of Everest. If you want multiple biomes, how effective can your 1 acre tundra section really be?
At a guess, I imagine they’ve decided an animal park in Florida most realistically showcases hot places. The Blizzard Beach treatment is fun for a water park but would be ridiculous here.