I'm not sure what the guys have in the plans for future development so I'm just spitballing here...
Just going by the original vision, the gas shortage and difficulty to build were an intentional balance to the amount of cars you could find... The idea was, yes there's a lot of cars, but repairing and gassing them was the balance/challenge.
Now, the issue is, vanilla. Removing the (easier) vanilla vehicle system as well as disallowing other vehicle packs *should* make it a bit more balanced, but each player decides that.