-1. At current state, having the equipment dealer in the city encourages members from each faction to venture out of their base. Its purpose serves to give each faction a reason to use other facilities of the map, not just the FOB, and other bases. It also fills up the negative space of the map, without it, there wouldn't necessarily be a reason to go to city.
Also I don't wanna keep dealing with fucking US camping on their walls all the bloody time. Having multiple dealers would just steer people away from combat even more and would permit US to camp their base more.