Fertilizing is a cash cow for tree services. So much so, it's hard to look at fertilizing critically. Years back when the industry decided Nitrogen applications did more damage than good, they needed a good way to justify fertilizing, and they came up with the aeration idea, mychoriza, beneficial bacteria, low fertilizer fertilizing, deep feeding, and a few other justifications to continue to milk the cow.
I have free access to spray rigs set up to deep root fertilize, with all the latest products, and I have several mature trees on my lot. I have no interest in using any of it.