You are right in the first part.But you've made the assumption you're actually burning 100% of the fuel your engine ingests and in reality it doesn't especially in low comp engines. If you're only using 70% of the energy present in the fuel and that's all your capable of utilizing with all the factors involved then yes you need more air and fuel to do it.
Now if you can extract 95% of the energy present in the fuel then you're making more power with the same amount fuel and air aren't you?
