That's backwards. The large energy requirements are exactly why trucks will electrify earlier: as far as useful energy goes, electricity is usually MUCH cheaper than diesel. The more energy that is used, the greater the benefit of electrification.
GGE for #2 diesel is 37.5kWh @ 50% efficient(which is better than gas) gets you 1.875kW per mile or 562kWh battery pack if you want 300 mile range before charging.
Current Model S packs are 1,300lb per 100kW so you'd be adding over 7,000 lbs just for a battery pack of that size.
For short-haul commercial stuff that's something you can plan for but I don't see a consumer who infrequently tows to variable locations making that work.
For reference your average 30MPG commuter needs only 0.33kWh per mile(and is almost exactly what our Model S does).