Direct Trade Question

Just a quick question. In Direct trading, there is a list of products available. Just wondering how these particular products were chosen. Some of them will always have utility. (officers,soldiers,cargo shuttles, even construction is in constant demand.) Why the others? Are they perenial losers as corps? Do they factor in unequally in Consumption Quality (kind of like the Dow Jones)? In constant demand across the words vs other products?

Cordially yours,
MNey

You give some people waaaaaay to much credit...

Some of them can't be moved on shuttles which is why I assume they are there.