Here in Charleston SC there are several micro-breweries that get represented in my favorite indie coffee shop downtown.
Westbrook is an amazingly good little brewery, especially their One Claw. I couldn't suck down enough of it when I visited last year.
Beer is a big hobby of mine. For reference, in the 1890's the US was up to about 2,000 breweries, largely because without refrigeration you couldn't ship it very far before it spoiled, so you had to have a ton of regionals. Once refer train cars became common, they began a period of consolidation that, in combination with the 13 year hiatus known as Prohibition, managed to bring that number from over 2k down to about 70 breweries left in the US in 1970. It took an underground (illegal) group of homebrewers around San Fran to bring it all back, starting with one brewery (New Albion) which showed everyone that it was a thing that was at least theoretically possible... New Albion failed a few years later, but their buddies Anchor and Sierra Nevada didn't.
Majors are losing share every year, and not growing sales, going back to about 2009. Only micros are growing sales and share, and by double digits annually ever year. For those owners of micros who become nationally successful, brewing between 30,000 and 100,000 barrels a year, they have the alluring possibility of selling out to one of the majors for millions. Some do it, as Elysian in Portland just did (and in their case, the employees found out about it when it hit the press... which is a textbook case of how not to do it). In the case of New Belgium in Fort Collins CO, the owner gathered everyone together, handed them envelopes, and had them open them to discover she'd split the brewery ownership shares evenly amongst them, meaning it's owned by them collectively and cannot be bought out unless they all vote it.
Fun Final Side Note: Bud bought Elysian. They paid $30M. Several weeks later, they aired an infuriatingly stupid ad during the superbowl aggressively making fun of craft beer and its adoring fans, specifically saying "you can have your peach pumpkin ale, we'll take our" whatever beer. Elysian, who they just bought, actually makes a peach pumpkin beer. ... the ad cost $8M