As the creator of the monstrosity, I will hopefully be able to answer your question.Well played!
Could anyone enlight me the purpose of making the mainland *visible* in the immigration map (or whatever it's fancy name is)?
As the creator of the monstrosity, I will hopefully be able to answer your question.
The middle is always visible due to players consistently placing their town centres in the middle in the past. Back in earlier versions, the centre also had a lot more food than what's on it now, meaning that it was a no-brainer to go there.
I tried to tackle this by decreasing the food and making the middle always visible, hoping that we'd see players finally go to the outside - and so they did. All of them. All the time. In hindsight, it wasn't my intention to make the middle so unattractive that nobody settles there, but at the same time, I wanted something unique for the centre as the map is called "Lost Island" meaning that the island is the point of interest on the map or that it at least holds some unique properties.