Whenever my players get involved in an Endeavour which involves shipping large amounts of goods back to Port Wander (and thus the wider Calixis Sector) I generally assume that transports have to be involved. That is to say, when the Explorers set up a mining colony, or establish a trade route to a distant world, it seems natural to assume that this would involve having a vessel which would come and pick up the ore or whatever good is being traded, and haul it back, presumably bringing something back with it to leave at the colony or sell at the trade stop. Usually in the past, I've had it that the Explorers could either contract a Free Captain or a shipping cartel to take care of that for him, or they could use a transport they own, buying one if they don't own one. (the latter would seem to be more of an option for more established Rogue Traders, however)
Is this how most players handle it though? I was noticing in the rules about Endeavours that none of the requirements mention these NPC transports doing milk runs, but it does mention Rogue Traders doing plenty of cargo runs of their own - and of course player ships usually have cargo holds themselves. This confuses me a bit, because I wonder if I'm missing something. I had always assumed that because Profit Factor is not a single sum of finite wealth, but rather a continual income from investments, rents and commerce, that the Endeavours would naturally be aimed at setting up a more permanent source of wealth. But it seems like it'd be incredibly boring for a Rogue Trader to use his fancy Sword-class frigate or Lunar-class cruiser or what have you to be picking up Naduesh silk and then running back to Port Wander to sell and then making the return haul with whatever Naduesh wants. Not to mention that if a Rogue Trader spends all his time doing this, he certainly can't spend his time pursuing new Endeavours!
Am I missing something? Should it be assumed that these NPC milk run transports are being used? If so, what kind of cargo runs should I expect the Explorers to do?