No, the final season of “Game of Thrones” wasn’t a disappointment. It was an insult. This fiasco was, of course, an insult to the tens of millions of fans who had invested so much time and energy in this series over eight extraordinary years. But in a more tangible sense, it was also an insult to the many more who own stock in HBO’s parent company, AT&T T, +0.09% If you have money in a regular U.S. index fund, that includes you. AT&T’s management has just needlessly thrown away a prize asset for no good reason whatsoever. Imagine the Empire State Realty Trust ESRT, +0.13% knocking down the Empire State Building ... (full story)