Instead of letting people just pull vehicles/MAX suits when they have enough resources, make them work to get credits. Sort of like the medal system. When they earn enough kills or enough points through repairing, they get a credit. Then these credits can be used to pull a vehicle.
Does this mean I got to go outside of my god-machine to live like a peasant for a portion of my playtime?
You just described the Resource System. I'm not kidding. You earn resources by earning XP. every so many XP you get a resource, in addition to the "ticks" that happen by default.