I built 6 trade routes and by turn 100 I've got maybe 10 total routes (mine and theirs ) for maybe 100GP total coming in
the rest of economy brings in about the same at 50% tax rate at that time except for
TOURISM! which has me in the 1-2k range, depending on map size, etc.
Without tourism, trade would be a useful add. in the presence of tourism, shouldn't really be a consideration