Yes NPC will be the life blood of any settlement and getting them on your side should be a high objective.
if NPC AI is done right they should be just as needy as PC but more activly do things as they never log out and will just continue tasks based of there needs system.
but lifes are finite thats why when it was first said they would only have 1 life alot of us got concerned. but i believe SBS is chaning how many lives a NPC will have based off some internal system they have which i hope is true.
because as i see it other then some players being more industries the only other PC has over a NPC is there number of lifes.
the other thing is that a npc you could set a task to travel 3 kingdoms over and deliver a letter.
now figuring that a NPC and PC would both use realivty same amount of stamina so roughtly have to stop as much as the other.
i would give the PC bonus for picking a shorter path and reacting to events and threats better but that player has to log out... no way they could personaly travel 3 kingdoms without needing to log out unless they are a very very dedicated player with no rl work.
so when the player logs out what ever lead they got on the NPC will be lost and if they are sleeping on a avrage of 7hrs thats 7 hrs the NPC got ahead of u.
then if u have a job and work roughtly 8hrs thats another 8hrs the npc was happly traveling. so when u login the avrage joe would have lost 15hrs on a NPC and that dose not include travel 2 and from work or anything...
so in the minority of players who can be online with just 6-7 hrs sleep and play thru the day every day nearly every one else will under perform in certain tasks vs a NPC.
with the way people are saying the OPC scripting will be they wont be able to compete in certain tasks like the one i used as a example.
they may be able to compete if say they are the owner of a black smith and set the opc to be forgeing iron why they are off line. this is one of those cases where a PC could possably keep up with a NPC but a NPC would probly also be doing things like researching better forgeing methods. maybe activtly interacting with cusomters and such.
sadly there is a gap the PC and OPC just cant fill that NPC fills perfectly.
to say that there will eventually be no NPC and all players is both scary and restricting as there will always be a place for NPC workers