Genuine question: Wouldn't this require a lot of ventilation / HVAC infrastructure?
It seems like in order to get 'really quiet' you need to have solid, noise-insulating walls on all 6 sides, which then makes it harder to ventilate (i.e., each cube gets it's own ductwork)
That said - I also like quiet spaces and if I was looking for a co-working space something that's mostly small, cozy, and quiet cubes would be perfect :)