Semi's actually get ~6.5 MPG so they only need around 5x the batteries to get the same distance as normal electric cars. The huge tanks are over 24 hours driving time and are most there so you can pick the states to refuel in.

Battery volume and weight density is not that bad when you consider the weight savings without an IC engine, transmission etc. Gasoline gallon equivalent tables ignore the vastly lower efficiency of IC engines. Costs are mostly non issue as trucks would charge daily making them break even before cars.

The actual problem is manufacturing capacity which has been ramping up but has a long way to go.