I'm on board with the theory. I see that keeping trees too long in pots makes them weird.
This explains it pretty well.
webpage
But who really knows if afterwards these trees with an unnatural amount of side branched small roots will indeed develop a strong rootsystem with a thick strong penroot and strong thick rock crushing side branching roots? I believe these air pruned trees get the immediate start most replanted trees don't have. It makes sense, they will quickly capitalize on the surrounding nutrients with their well developed small roots system. That is not a guarantee that long term growth will occure though.
The old system might not be perfect, and it might take a long time for trees to really get started, but i seriously doubt this is a tried and tested method. In the long run your air pruned trees might all blow over by the wind. Is it really great to have a lot of first year growth in leave volume and branches above the ground if the ankering is not keeping up?
I'd like to be proven wrong, but my liking of Akiva Silver, i loved,loved ,loved his book is not going to keep me from expressing my doubts.