I am not sure what Detroit did to "try too hard to retain manufacturing." I'm not even sure what that means.
What it did, as far as I can tell, was keep building infrastructure, hiring people, and otherwise spending money as if it would always be a city with a growing tax base. When the then-current tax base wasn't big enough, Detroit borrowed money to fund operations and promised big pensions in lieu of current salary (which is basically the same thing), promising to pay for it with future income from that theoretically always growing tax base. Amazingly, they continued to do this long, long after the point where it became crystal clear that Detroit and it's tax base were actually shrinking, and would continue to shrink for the foreseeable future.
It is critical and frightening to understand that hundreds of cities across the country have been and are continuing to do exactly the same thing. In Detroit, the tide went out and revealed that Detroit wasn't wearing a swimsuit. The same thing can happen to any city, it just happened more dramatically in Detroit. For most cities it is still working kind of OK as their tax base is continuing to grow to some extent, but another recession or a big crash in a critical industry could do the same thing to a lot of cities.
