There is a residual talent pool of generally undervalued developers in every urban area that is not Boston, NYC, Seattle, and San Francisco. Lots of smart, ambitious people simply cannot relocate to trendy areas.
There are fewer startups, and fewer resources for those startups, in Minneapolis. However, that doesn't mean there are no startups there.
Meanwhile, cost of living and competition differences in underutilized areas make startups in underhyped areas more efficient and easier to staff, up to a point.
I really wonder how much this meme about how much easier it is to staff in San Francisco comes from social ineptness. It always seems like the people infected with it simply can't conceive of recruiting in any way except national job postings and IRC. Our last 3 hires came from meetups we organized.
Finally, if you're really freaked out about finding developers, put your money where your paranoia is: hire remote devs.