Gilbert stroke a reminder Detroit's comeback still fragile

Dan Gilbert (Photo: David Guralnick, The Detroit News)Mackinac Island -- News of Dan Gilbert’s hospitalization for an apparent stroke is a jarring reminder to Detroit of just how much of its well-being is invested in one man.

No other city in America is as heavily dependent on the commitment of a single individual as Detroit is on Gilbert’s.

More: Dan Gilbert hospitalized with stroke-like symptoms

The head of the privately owned Quicken Loans/Bedrock/Rock Ventures empire has over the past decade invested nearly $6 billion in rebuilding the Motor City. He has rehabilitated, or is in the process of doing so, roughly 100 buildings across downtown, transforming the central city into one of the…