Not that it should surprise anyone, but brewing giants like InBev and MillerCoors aren't buying craft brewers to distribute them more widely. Just the opposite:
[T]he Department of Justice and regulators in California were investigating whether InBev, which makes Budweiser and Bud Light, was buying up beer wholesalers to curb sales of craft beers in bars and grocery stores.
“When a big brewery buys an independently-owned distributor they would evaluate each one of those brands and not keep all of them,” said Tom McCormick, executive director of the California Craft Brewers Association and a former beer distributor. “The bulk of their attention would be on their in-house brands.”
Even as the big players merge, they may not be able to run ahead of consumer tastes. In the last 10 years many Americans have cut back on beer in favor of wine and liquor. And though InBev is very profitable, its beers have been losing market share as more people buy imported and craft beer. [Brooklyn Brewery founder Steve] Hindy said that’s because smaller brewers are just more single-minded about taste. “We make beer,” he said. “They make money.”
The craft brewing phenomenon terrifies companies like InBev because it's literally impossible for them to compete with micros. Once InBev buys your micro, it's no longer micro. You can't scale a micro up very far, either, or it ceases to be a micro. (See, e.g., Boston Brewing Co. and Goose Island.)