Assuming you're not trolling but want a real answer: Because the Emperor's New Shield replaced the invisible shield we got during the Garo-event - it was part of the Garo-gear you could buy from the Gold Saucer (undyeable version, didnt unlock the titles, not possible to buy it back from the calamity salvager). To keep it consistend between the different jobs, all Gold Saucer Garo-gear was priced at 100k. To keep it consistend (and with that fair to anyone who bought the shield during the event) after the event ended, they kept the price.