Your comment on the Arborist being paranoid and handling trees as though they are fregile.
I will agree but with a degree of skepticism. The way I see it is this!--You go out and investigate a 300 year old oak that is 15 feet in circumference and is 80 feet tall whom is dying from Lord knows what. You spend a hour digging around the base............looking into the canopy with binoculars for signs of decay, holes,cracks,rodent entry,etc. Take samples to the State Guru's......perform the Resistograph tests to check the integrity of the wood inside for heart rot and decay. Sometimes, the right thing.......the correct thing isn't always in perspective. A tree of this magnitude will cost in the lower 3-5 thousand dollar range to remove and de stump if you screw up.............and it is at your expense. So, I am with the Arborist's whom are anal and are pessimistic about just jumping over barrels here on touching a tree's natural existence. Mother nature puts trees all over this planet by seed, nut, wind dispersion,etc. Where they choose to root is up to the growing conditions. This site isn't always the best place as only nature can dictate. Humans come in an plant trees, plants, shrubs and grasses in valiant hopes to create something impressive and massive to admire. Only nature can choose the weak from the strong............................all we can do is offer advise and hopefully administer tidbits of knowledge for an ailing tree that has evidently been incorrectly planted in the worse care scenario.