Contrary to popular belief, a large root mass does NOT necessarily equate to more nute uptake = better bud mass. Low Pressure Aero, DWC, and NFT roots are often reservoir clogging huge, but they lack efficiency. Look at those root pics you will notice that they look like a mass of swollen spaghetti noodles. Sure they grow nice plants, but so much more is being harvested from smaller root structures, where the environment is favorable to the root developing fish bone like structures (as seen in the AP video), which CAN lead to root hairs.
Root Hairs are very tiny and look like cotton candy. The amount of surface area is exponentially larger than LP/NFT/DWC rootd
The most efficient root structure is that which develops in a High Pressure Aeroponic environment. I have been using HPA for 5 grows and when all the parameters are dialed in, HPA out performs any other method. I have a journal comparing HPA v Flood & Drain v Air Pot. I started one plant in a 4" AP and after a week transferred it to a 1.5G AP. The roots were very similar to HPA roots. AP is a whole different ball game for soil growers. I pulled that plant as it was a male, but was very impressed with how thick the main stalk , primary leaves were.
Most soil growers use pots that are too small for the size plant. Until AP, the rule of thumb was 3 ft plant needs 5G pot. Based on what I saw with my male plant, my gut tells me you can easily grow a 3ft plant in a 1.5-2G AP, That is a huge advantage, plus the root structure is superior.
I have a bunch of clones rooting right now, so my next test will be all the same clones in the 3 different mediums. All will be under the same light as I am using now: a Quantum Bad Boy 8 bulb HO T 5 mixing Quantum Bulbs with coral bulbs. hth