Is it even more odd that I can't figure why they did not reference the literal movie 'Battle Royale' that the concept was roughly based on?
Internet was hardly available in the year 2000. It takes a lot of bandwidth (and probably CPU too) to run a 100 players FPS. It wouldn't do well before broadband got ubiquitous, almost a decade later.
That doesn’t change the fact that BR predates the hunger games (though the author claims to not have heard about BR when she wrote the hunger games).
BR is supposedly about how the old of japan are metaphorically sacrificing the youth. The hunger games was (according to an interview) about reality tv meets the war in Iraq.