Can't figure out what I'm doing wrong

[Graeme Dice]

Sandman said:
Three researchers is very poor for the middle of the second year, although Jomon doesn't have good mages to begin with.

What gives you the idea that their mages are poor? They are dirt cheap, and you will easily have multiple mages with two picks in a single path, plus guaranteed astral and nature magic. They are every bit as good as Arcoscephalian mystics used to be in Dominions II. They are probably the most magically diverse nation in the Late Era.