That's a reasonable way to think about it - you take energy from the supply voltage to charge the gate capacitor when the logic line goes high, then dump it whe

That's a reasonable way to think about it - you take energy from the supply voltage to charge the gate capacitor when the logic line goes high, then dump it when the logic line goes low. If you had a lossless bidirectional voltage converter circuit for each gate capacitance, then you could charge the capacitor from the supply and discharge it back into the supply, removing any switching losses.