Ryu is definitely far more iconic than Master Chief at the very least. Outside of Mario,Sonic,Pikachu ... i'd say next in line would be Ryu,Scorpion. SF2 has far too many references in mainstream media.
I think you are seriously underestimating just how big SF2 was , especially worldwide. Master Chief and the Xbox itself is quite niche outside of the US.
See also: List of highest-grossing video game franchises This is a list of the highest-grossing video games of all time. The list includes games across all platforms (including arcades, consoles, computers, mobiles, and online) that have grossed at least $1 billion in revenue. The revenue...
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SF2 was a monster in the early 90s , and arguably the biggest game of that era comparable to Fornite and GTAV of today , except with much lesser competition ( which means far more visibility ). Not to mention it has expanded on to multiple other forms on media like Anime,Movies,Comics..etc.
VS fighters maybe niche now , but when they were big they definitely broke into mainstream consciousness.