A funny thing happened this year as investors dove into e-sports, chasing eight-figure franchises in the Overwatch League and the “League of Legends” League Championship Series: A new game came out of nowhere to win the hearts and minds of fans. Launched in beta mode by Korean developer Bluehole Studio in March, “PlayerUnknown’s Battlegrounds” is a bona fide juggernaut, and its rapid ascent raises fresh questions about the wisdom of relying heavily on any single game for long-term e-sports…