That's just the thing: it doesn't. In fact, it makes it more difficult for new breweries to break into the market. Every brand that ABI acquires is more power they have to control shelf- and tap-space, and to drive down the market price of "craft" beer. Those factors make life much more difficult for start-up breweries.
Do you really believe this? I cannot attest to the craft beer market in Indy (nor have I tried to open a brewery), but in Nashville the number of craft breweries has grown exponentially in the last 5 years. Trust me, I've been waiting for the price of craft beer to be driven down, but it is rock steady. If anything, it has increased over the years. Also, I've really only seen expansion on the shelves in favor of non-AB craft breweries, and they're mostly >$9/6-pack. Not cheap in my eyes...but I pay it because I like their beers.
I was never a fan of Goose Island's beer before AB, and guess what?! I'm still not a fan, so I still pass them up for other beers that I like. However, I like WW beers so if they start distributing them here then I will probably buy some every once in a while. If AB wants to sell them cheaper, then it's a win for me.
The issue isn't really about what's good for the brewery or for the consumer. It's about what's good for the craft beer movement as a whole. Budweiser already clawed their way to the top of a heap of conquered breweries once. It is fairly obvious that they are waging the same war again.
I'm not sure AB is trying to wage a war on craft beer to abolish it as a whole. I think If that was the case then they would be trying to purchase every craft brewery that opens, and they're not. It seems that they're making
business decisions to purchase these profitable breweries in order to increase revenues. Like any other big corporation does...
If AB starts buying all the major malt, hop, or yeast companies only to raise the prices then I will get worried about the "craft beer movement."