I dont think hes trying to say he wants to do UC in soil, more that he's in soil now and wants to go UC. And yes, UC/RDWC is IMO probably the best way to grow trees. Aero, E&F, NFT, hempy, etc. are all great and have their advantages, but UC has explosive growth rates and are typically larger containers that can support bigger plants. Seems to be the most popular choice for people wanting lower plant counts with huge yields.
Im sure you can get a lb per plant, just use enough lighting and very few plants. Most people don't care to get that much per plant because it takes too long to veg. Why not grow twice as many 8oz plants?
UndercurrentDWC has a great thread on here, and thcfarmer has an awesome undercurrent section. Lots of pros and industry support there.