Interesting to look at the big 4 US sports:
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football: invented in the US, never really exported, US's undeniably the best
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baseball: invented in the US, exported to East Asia and the Caribbean. World title is contentious with japan with the most titles, but also because top US talent doesn't participate in international games
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basketball: invented in the US, exported to the balkans, US still the best
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hockey: invented in canada, exported to countries where ice exists, Canada still the best with most world titles
So I'd say Canada is the best at making a sport, exporting it to a decent amount of countries, and still dominating the sport.