Here’s a thought I had over a lunch of Mee Goreng and Rojak. As the cost of transportation declines there is a non-monotonic effect on migration. Decreasing transportation costs make it cheaper to visit and discover new places. But for small cost reductions it is still too costly to visit frequently. So if you find a place you like you must migrate there.
For large declines in transportation costs, it becomes cheap to frequently visit the places that you like and you would otherwise want to migrate to. So migration declines.
The same non-monotonic effect can be seen as a function of distance. For any given decline in transportation costs migration to far away destinations increases but migration to nearer destinations declines.
For the vapor mill it means that over time between any two locations you should first see migration increase then decrease. And the switching point from increase to decrease should come later for locations farther apart.
By the way if you would like to see more pictures of delicious food in Singapore you can follow my photo stream. But beware it might make you want to migrate.