Your point is still not substantiated. There are many language pairs closer than Esperanto (I mean, there exists x and y such that `d(x,y) < max(d(x,eo), d(y,eo))`), even after the easiness due to the artificial origin is accounted for.
Of course there are languages that are so close together speakers can understand each other without even studying.
But I'm sure there is no language (with at least 1 million speakers) which is easier than Esperanto to learn for the average Asian. It isn't a European thing.