

Lots of great answers already, but one interesting thing that seems to be like it would keep more mammals from evolving to fly:
extra weight of the young during gestation.
Egg-laying birds get to breed but don’t carry around that extra weight for nearly as long or as heavy. That’s got to be a huge evolutionary advantage, right?
Pretty sure it was the other way around, if your analogy holds at all. The original government fled to the island as Maoist communist rebellion took over. So it would be like if the Union was on the island and confederates took over the mainland.