It is easy to understand. Think about trying to pedal your bike in the mud with 5mph. You will run out of energy way earlier compared to biking on perfect, flat tarmac with 10mph.

To overcome friction, you need additional energy. The electric F150 comes with ~3.7 gal equiv. of gasoline worth of energy. The gas powered comes with ~25 gal tank.

If we assume 90% efficiency for the electric motor and 25% for the gasoline, you get:

electric F150: 3.3 gal equivalent available to move the car

gas F150: 6.25 gal equivalent available to move the car

The gas-powered stores effectively double the amount of energy, if the two cars have equal weight and aerodynamics, the gas powered will have 2ble range.