Maybe a more apt example is "Hey WB, Marvel just made a huge amount of money making a 'Shared Superhero Movie Universe'. You should do that too".
Although I guess WB is finally starting to make good movies in Wonder Woman, Aquaman, and maybe Shazam?
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In any case, I agree with you. Battle Royale games are clearly the hot new thing at the moment, but Hearthstone (Blizzard / Activision) basically created the online collectable card game (yeah: MtG is the original game, but it never had a good and/or profitable video-game version before Hearthstone).
The goal of these game companies should be to discover the NEXT big game genre. Battle Royale is big today, but it will be years before you can launch a new Battle Royale game on the same quality as Fortnite.
New Genres pop up all the time: MOBA (League, DOTA, HOTS), MMORPG (WoW, Guild Wars, Final Fantasy, Eve), and now Battle Royale. Who knows? Maybe the next major genre will be robot-cars with rockets on them that play soccer. (Rocket League, except no clones have been made yet!! Think about it...)