Automation is what MAKES them most efficient in terms of player input per resource output. It's the entire point of automation. And why would you still go out and gather? Because they're producing 10-20% of the resources needed to keep the economy going. When I say that, that's assuming every house, village, and keep spot is taken with the max number of automated things going at each of those locations.
So if you want to be a gatherer. Well there is still the other 80-90% of resources the economy demands.
But if that 10-20% isn't the best in the game, and it's also exposed to PVP, nobody will fight over it. Nobody will use it at all. If it IS the best 10-20% in the game, raiders will make circuits of automated gathering stations to steal it, and the owners will have to actually work to defend them. The limitation isn't time efficiency. It's a limited number that can be placed, producing a slow enough trickle that it doesn't rendering gathering redundant.