Stan, what do you find are the top differences between successful brewing ventures and unsuccessful ones? What are the keys that separate the "winners" from the "losers"?
Whoa, that's a big question - one I've been thinking about for two weeks since it was posted and still don't have a good short (or long) answer.
Since you used the words successful in the question I think figuring out what that means is a good place to start. Owners need to define success and how they will measure it, then ask themselves if they meet that measure it means they be operating a viable business. For instance, if having the No. 1 IPA at a beer rating site equals success then they might need a new business plan.
It's boring, but the only way to succeed is with an I-got-an-A-in-business-school quality business plan and sufficient capital to see it through. Of course the quality of the beer matters - both what leaves the brewery and what ends up in a drinker's glass.
A good business plan and good beer are a good running start. Something else I've found myself talking with brewers about recently is "scale." Naturally limiting size -- say selling beer only as far away as a horse can walk in one day, only on draft, and only to accounts that pour three a keg in a week -- eliminates the need for certain controls. Choosing to sell to a wider audience means you have to scale up. Deciding if and when to stop growing is one of the hardest decisions brewery owners have to make - and one more will likely be facing soon.
Sorry not to offer more specific suggestions. For me it might a forest and trees thing (or trees and forest, I never get those straight). Buy me a beer some time and we can draw some Xs and Os.
One other thought: Not every brewery that closes is necessarily a loser. It might not have lived up to (high) expectations, though could was viable. Or it might have succeeded for X number of years. It would be interesting to back through time and chart the history of every brewery that ever opened in the United States. How many of them lasted longer than one or two generations? How many post-New Albion breweries are going to end up multi-generation family-owned businesses?