Why Does My EV’s Estimated Range Drop So Much on the Highway?

My electric car’s range estimate looks comfortable around town, but it falls much faster once I’m driving at highway speeds. I understand that speed affects efficiency, but the difference seems larger than I expected.

How much do speed, temperature, cabin heating or air conditioning, and tire pressure each affect highway driving range? I’m also curious whether the estimate is reacting to my recent driving or recalculating the trip from current conditions.