You can already raise resources spending gold, Dectilon. Just take 1 less order scale and 1 more production at the same cost
It seems the game works perfectly as intended in letting your smiths, miners and lumberjacks produce a maximum total of resources per month in a certain region. If you want more resources, you have to design your entire society with much more production... just imagine the state gives gold to smiths to have many apprendices and bigger forges, to lumberjacks for better axes and to miners for safer mines
but it must be done from the beginning ^^