My father in law and I had a conversation this morning about this. He had an awesome idea:
Beyond the stubborn, hard to move people you also have a very large transient/homeless population inhabiting many of the abandoned buildings in the city. Set up a concrete and steel reclamation facility using one of the shuddered foundries and some cleared land. Give the owners a choice to bring the building up to code within 36 months or surrender the land for a 2 year tax exemption and a small cash settlement (land only value). If they surrender the property then tear it down immediately recycling the cement, steel and the rest of the building materials into simple 20 room cement structures that are engineered not unlike a county jail or prison placed throughout the city as transient/homeless shelters. The shelters would feature solar powered LED lighting and in floor heating. They would not be comfortable homes but rather hard generic cheap to operate and maintain shelters that hold 20-30 people. Build a nice apartment into the structure for live in building manager that works for the city for $10.00/hr but rent is included.
Offer demolition, removal and construction jobs to the locals and after these buildings are built offer them building manager positions. It gets the people working and helps the local economy. As the buildings start coming down begin to repurpose the land into useful industry, parkland or residences. If I recall there is a huge amount of acreage in the area that can be replaced.
The scope and size of the issue in Detroit is almost unfathomable.