Check out the growth of the Michigan brewing industry, detailed in this issue of Michigan Beer Guide. Yes, some breweries are closing, but new breweries are popping up to take their place, and many of the heavyweights (like Bell's, New Holland, and Founders) are expanding to fill demand.
On a related note, the article also references Bell's pullout of distribution to Illinois, covered in this article from the Chicago Tribune (link is to free abstract, you have to pay to read the article in full) and this article from BeerDorks.com, has been a hot topic among Midwestern beer folks. Not to worry though, as Bell's has picked up distribution in several other states and may be back in IL in about a year. And for you Chicagolanders making a trip to the source, rumor has it that your IL driver's license gets you 15% off.