>>understand that small-scale hypothetical first We understand it well enough to know that it does not apply. Flour in crevices is not a gas in a mix of gasses

>>understand that small-scale hypothetical first We understand it well enough to know that it does not apply. Flour in crevices is not a gas in a mix of gasses Your problem is you must pick the right small-scale hypothetical. For gasses, any single removing device operating faster than the input devices will eventually remove ALL of the target gas. Yes, the rate gets asymptotic, and yes, more devices are better than one, but every molecule will all by itself come out of every crevice, and eventually bump into the removal device. That will NEVER happen with your flour example. This principle is already used for pretty much every air cleaning device in use both on the planet and in space.