Battery weight is going to be a limiting factor until new battery technology is developed. Manufacturers are getting greater vehicle range in large part by increasing battery capacity, but there’s only so much you can add before the vehicle gets too heavy.
Battery capacity was initially limited mostly by costs, but now that they’re much cheaper per kWh, manufacturers can add more battery and range; except for the excessive weight.
For a cargo van where added battery weight reduces payload, this becomes even more critical. To increase highway range, manufacturers also need to focus on lowering drag.