I think we need a dissertation that really explains the marketplace. I see these people that are "off to get groceries", and I don't see the logic in what they do. ...
Such a dissertation would have had to come from the developers and since it would have had to explain the whole game - it was never in the cards. The Marketplace is just a single cog in a complex set of wheels within wheels - it doesn't do its thing independently. How it works depends on its location in relation to where the people spend most of their time.
It took years for someone to crack the game's scheme. The game people\units do not order their "days" as we do in the real world. For example, they eat only a few meals per year. The people rotate among six modes - one each for the five needs plus one for work.
I placed a marketplace right next door to an apartment that was full of miners and hotel workers. All of this was located 9 or 10 blocks from the nearest farm. Yet they only consumed an average of 3 or 4 meals a year from the marketplace.
Only six to 12 adults as potential users (no one else is going to walk there), yet islolated from three of the five needs satisfaction buildings. It is more likely that the people were off walking to or from a church, clinic, or pub when they went into the hunger mode. Upon going into the hunger mode, they go to the closest meal pickup - not necessarilly one close to their sleeping place (home).