Digging the good debate! Sorry, I wasn't trying to start a controversy here! My main concern with the rapid expansion is to do with major cities where already a good number may be established.
Imho it won't really be a "burst" like you see in the housing and financial sectors. People won't leave work one day to find that half of the city's breweries shut their doors *knock on wood*. It would more so be a shift in our domestic beer culture and the American capitalistic mindset. This could take years or decades to happen.
Let me elaborate and also pose a question. Do you think our beer culture/economy is going towards that of the Germans/Belgians? Every small town would have its own brewery, mainly for the locals? The big macro-craft producers (Sierra Nevada, DFH, Stone, etc) will still be there and more will continue to grow to that scale, but the AB InBev's and MillerCoors of the world will continue to shrink in market share. As to the change in economic mindset, we as Americans tend to always want to expand our businesses and acquire more space, market share, territory to sell the product, etc. In the near future (or now, depending on what market) every opening brewery can't open with these kind of expansionist goals in mind. Some will have to open and know that it will only produce beer for the people and bars in its backyard. To find that healthy economic equilibrium, new breweries will need to understand their niche in the local/regional beer market. Perhaps this will lead to the establishment of a more family and traditional business model for breweries. More local, more family based, etc.
