The issue isn't about efficient use of leg-power, but rather of design in the pump. Foot-operated pumps typically are for low-pressure/high-volume applications like inflatable mattresses or rafts. Thus, they have large-diameter chambers & pistons for minimizing the number of pumps needed.
Bicycle tyres on the other hand, require high-pressure/low-volume. Thus the smaller-diameter pump to require less force to generate high-pressures.
When I worked with in Mavic neutral-support van, they did have a custom-made pump with larger diameter that pumped on both the push & pull. Took only 5 pumps to go from 0 to 120psi, but it did require A LOT of force on the last two pumps. Anything needing more than that would require the smaller-diameter Silca pump, or the mini electric pump powered by the cigarette lighter (these can go 240psi+, don't walk away after you started the pump!).