I just don't get it. Is it the sales dropped as new breweries entered a crowded space and gravitated to something new? We've seen several of these recently with breweries you would expect to have a track record of sales to lean on.
Something I'm seeing locally is that as the number of brands goes up, the distributors do a more and more poor job of keeping stock fresh with "legacy" brands. New brands sell well, so the job is easy. "Old" brands have a harder time.
Reference Sierra Nevada and Bell's in my area. When Bell's first came to the area it sold like hot cakes, and fresh Two Hearted was easy to find. Now that Bell's is old news it doesn't sell so there's no fresh beer to be found. SNPA only sells during the summer here, for whatever reason. Usually come spring there's still 12-packs dated from August/September time frame still on the shelves.
Local brews, seasonal brews, and whacky beers sell. Sadly that's kinda hurting some of the better beers and brands, in my opinion. Brown ales aren't to be found on shelves here anymore. Fresh SNPA will always be a classic. This is why I drink Yuengling, it sells, so it's fresh.