This is unlikely, unless that area is already full of other competent players piloting good decks at least semi-sensibly - all of whom we also somehow haven't heard of. The thing with the elite level of any game or sport is that you need elite level competition to keep you on your toes. This is especially true in LCGs where metagame is a thing. If your local scene is full of chumps with no clue, you don't exactly have to raise your game much or make tight metacalls to stay on top and making those calls and adjusting to the local landscape are very important skills you need to have at the top of the game.
I'm not saying a local player couldn't possess those abilities, but if your local area isn't of a high enough standard to at least be net-decking good ideas and playing them well then you can't hope to hone those skills.
^ This. Actually it's not that unexpected in a large field with a proportionally small cut. In a field of 128 there could still be two players undefeated after six rounds of swiss, so if the very top players haven't necessarily all played each other then it stands to reason that the top-16 cut will have played a fair few scrubbers along the way. It doesn't take much for a couple of anomalies to creep in.
That being said, fatigue is also a thing and could easily explain some of the misplays we saw. It's certainly a factor in the new double elimination knockout format.
As much as I believe in statistics and large datasets, not all OCTGN games are created equal. How do you tell a game where someone is experimenting with a new build vs. a mate, from a serious game?
^ Solid brag
It's a bit tricky to see where Europe fits into the picture as well. Undoubtedly there's some talent over here too, but very few of us can make it to the big US events and our scene is much smaller. Regionals in the UK seem to be about 40-50 and largely comprise the same core of regulars who will travel, plus local talent. Our Store Champs are variable too - some were nearly as big as Regionals, but others were 4 players and it seems wrong to treat them in equal esteem.
A mate of mine, who doesn't post on here, won 3 Store Champs, runner-up at another, won a Regional and placed top 10 at Nationals - but all with the same two decks. I'd say he's a good T1 player who I would expect to be there or there abouts in most "normal" fields, but is he outstanding or did he just find a good deck for state of the meta and milk it?
I would class myself as a decent theorist, but I don't play enough to really to class myself as genuinely T1. I won a Regional last year and made top-8 in London this year, but I only play the big OP events becaue my time is too stretched to fit in local events and all the testing that's necessary. Being good at this game isn't just about knowing what you can do, it's about knowing what your opponent might be trying to do and how to adjust accordingly - you can only get that through playing and reading a lot which is why you need a strong local community and/or a way to access opposition from elsewhere, such as OCTGN.