That tree looked pretty far gone.. I have yet to get an air spade/compressor, so my personal experience with soil remediation is very limited. I've seen good results from vertical muching on fairly healthy suburban trees.. BUT with a tree that far gone, I think the vertical mulch is not enough to turn the tree around..
Radial trenching would be a more agressive and appropriate course of action. What is the history of that tree/construction? How long ago was the building put in.. Were the roots buried/compacted or excavated with a bull dozer... Looks like few, if any roots survived beyond the sidewalk..
Though tulips do pretty well post-contruction, it would be surprising if that tree did anything but die at this point. Still, with such a magnificent tree, its good to see someone trying to give it a chance. And its a real shame they didn't so more to protect the tree in the first place.
JMO, would like to hear others'.