A pattern of not learning from mistakes puts a target on your back.
WotC keeps repeating basic mistakes. They don't know how to market. They offended large swathes of their audience when making 4e (losing a lot of fans to Pathfinder), and now they're insulting their audience when making 5e (4e fans can go elsewhere is the attitude I'm getting from them). It's not the same set of fans being insulted, but you don't need a marketing course to know that this isn't a good move. It's also the same mistake they made only five years ago, and they have many of the same people now as they had then. Maybe their position in Hasbro makes it nearly impossible to hire a marketing guru, though I find this hard to believe (someone is marketing their books, someone is marketing Magic the Gathering, someone is looking up marketing techniques on Google, etc).
Then there's the playtest, which is being botched. I don't know why. Maybe it's not Mearls's fault, but he's acting like it's going just fine and it seems like he has to be publicly embarrassed before he will acknowledge a problem. Witness the "ghoul incident". (Yes, there's people who think ghouls should be that way, but even so, Mearls shouldn't be surprised, considering the issue is the "core" of the game system.) The upset fans left, leaving a smaller group that are generally happy with the way things are and skewing the results, drowning out the remaining unhappy fans' survey responses. I don't think the surveys are particularly good at collecting information, either.
WotC isn't the only company that goes through this. Companies and organizations I deal with a lot (Blizzard Entertainment, Wikimedia) go through the same thing. I generally only get upset if a mistake is repeated, or if a blatantly obvious mistake is being made. WotC is doing both.