You say that with such confidence like there was no Zelda game before BotW. Go look at all the articles, videos calling it the Zelda killer. Then look at all the outrage why BotW won GOY.
The one thing you are right on yes they came out at about the same time so what Horizon was, was never going to be a direct battle against BotW but it's predecessors. I would argue not many people thought BotW would be such a significant leap from the previous game that it surprised many when it come out
Who ever called Horizon a Zelda killer has no idea to what they are talking about.zelda is the best gaming franchise of all time. You can't compare it with some developers that haven't even made a big hit. They still don't even have one game with a 90 metracritic.