Sam Adams sales continue to grow, but their percentage of "market share" has declined. So the ad blitz is to fight back for market share.
Market share is important because shelf space is valuable and big box stores and supermarkets won't waste shelf space on items that don't move volume and produce profits. Bars also don't want to devote tap space to beers no one has heard of, or they only have one or two taps of specialty beers, so brands like Sam Adams have to keep their name out there all the time. Some Sam Adams beers I like a lot, others not so much, overall I think they have a pretty good product mix.
I really like their latitude 48 deconstructed 12 pack. You get to taste their base IPA made with individual hops like EKG, Zeus, Mosaic, Hallertau, and Simcoe, along with the "48" that has all those hops in it.
I don't buy into the "its big beer so its crap" line of thinking, although for some beers this rings true. Sam Adams is a big producer and they make some good, and some above average beers, I wish I could be one tenth of one percent as successful as billionaire Sam Adams founder Jim Koch.