You are absolutely right on that, but the 2 stroke engine is not that good in volumetric efficiency, its the actual "one combustion per every other stroke" what makes "the good overtake the bad", BMEP on the racing 2 stroke usually is not high compared to the 4 stroke counterpart, which is the real measure of efficiency and thus, torque production at a given rpm. The 2 stroke combustion process is very dirty, the fresh mixture mixes a lot with the used one, so it's unlikely to get the eficiency of a 4 stroke if we consider only the power stroke, the 4 stroke's cycle stages are so well separated that they can do their respective jobs better, without the intrusion of the next stage. It's easy to see that in a 2 stroke, the overlap of the intake ports with the exhaust port is 100%!, in a 4 stroke is what, 5%? just around TDC.
So what I'm sayin is that the 4 stroke uses more air, rpm being the same.

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