erm, that makes the assumption that the goal of taking the new place would be worth it. Like I said, tactical or strategic value might come into play.
Not quite following you here.
Perhaps the bandits are based in the west, have their strong ones there, etc., and are sending out the weaker bandits to attack the weaker targets? Why waste strength on the weak? Keep your battled-tested and smart ones to the rear where they can train the new ones and plan to take over the world.
Math lesson
- lets assume that there are 3 groups of bandits in the world, lets assume as you say that they are all based in the west.
The world: we already know that the land of skyrim has 5 glorious citys splitting all over skyrim, so there is no such thing as unprofitable east and profitable west.
Now for the math - 1 group of bandits is sending her weaker link to attack the weak east, why wasting strong troops on an easy target, as you said.
following action - "Oh no!" says the 2nd bandits group. "We wont let them take the east for themeselves! MOAR STRENGTH TO TEH EAST I SAY U MAGGOTS!" and so, the 2nd bandits group is sending their medium-strong bandits to take over the first group.
following action next - "I see" says the high ruler of the 3rd bandits group while brushing his long gray beard with his hand "Gather near and listen my honorable bandits. We are not going to let those weaklings take over. Send our best men, and bring the treasure to me." he waves them off with his hand, and so the 3rd bandits group is moving strong towards the east to take over.
And so on.
Edit: my math lesson became a bed-time story. Oh well