Death? No I don't think so, for me as long as internet is there Bitcoin won't die. And about the tax thing, don't be disappointed about it. Because everything must be fair among all their citizens, and if they refused to accept taxation they might be punished by law or worst jailed. Also this is a good step for bitcoin in South Korea, because addition of taxes means bitcoin is being legalized and accepted on their country. Sooner or later other countries will follow Korea actions, meaning total legalization and adoption of bitcoin in this world is not that far.