Flint's population has rapidly declined over the past 40 years and continues to decline (its population is less than half of what it was at its peak), so there's not a population boom driving up demand. Flint is not exactly known as a tourist destination either. And to top off, Flint is most well known for its contaminated drinking water that contains lead. So why on Earth would such a place be experiencing a housing shortage?
The obvious answer is that governments around the world have brought interests rate down to zero, which forces investors to seek out riskier and riskier assets to invest in. Instead of investing in traditionally safe assets like treasuries and bonds, investors now have no choice but to invest in stuff like tech startups, cryptocurrencies, personal loans, mortgage-backed securities, and dilapidated houses in the Midwest.