Samura might be incredibly huge and encompass most of the kusarian economy, but that does not mean in the slightest that it could go on par with the other houses, why? Because for Liberty, you have USI, DSE, Ageira, IC. Bretonia has their gigantic Bowex as well as BMM, Gateway and let's not forget Planetform. Then in Rheinland there's DHC, Republican and Kruger. Samura might be larger than one in any house, but not a whole house's.
Each faction has it's own thing, either resource gathering, technology and/or shipping (shipping being the real source of income) and are somewhat evenly distributed within that House's respective economy.
Economy is -not- a one sided thing, it doesn't work one way and if people think it does then they should read up on some general economy. While the other houses have more or so open trade (other than their war fronts) and with multiple groups, Kusari is one sided and as you've said yourself, is mostly Samura. Samura alone cannot compete with the rest, not even close.
And as I said, economy isn't a one sided thing, when you practically have no foreign imports, the economy -will- crumble because the other houses are doing free-trade, while one isn't.
Kusari seems to be ok at the moment because of forced trade with Gallia which brings them quite a bit of resources and income because Gallia is easily self-sufficient. But going back to old-kusari pretty much screws that over.
So yes, Kusarian economy is strong as a single entity because it's a house. When compared with the others Houses however, it has severe disadvantages that would put them on the lowest of the scales, because the rest (especially Liberty) are much more powerful in that aspect.
