Why is there not a diffuser for each plant in an GrowStream growing chamber?

The level of solution in the chamber is generally adjusted so that 2/3 of the root mass is submerged. Diffusers are made to oxygenate the nutrient solution, by spraying drops into the air, stimulating circulation of the solution and cascading down the walls of the chamber. The diffusers are not made to water each plant individually. It is recommended that you position the diffusers towards the walls of the growing chamber and not towards the roots