One way or another, Kusari is shafting itself.
For a few ships they have cut themselves off from the largest trade market in Sirius.
That would be like Ireland cutting off trade from the USA. It might hurt the USA but honestly, Ireland would be utterly screwed.
The argument that Rheinland is making up the rest of the trade is pointless.
If they were making it up why were they not trading as much before the embargo?