I'm not a wine connoisseur, but it seems to me that everyone is making wine these days. It would be interesting to see who comes out on top if this test were done with a variety of wines from different regions of the world.
The US wines would consistently be at the top for several varietals.
"It would be interesting to see who comes out on top if this test were done with a variety of wines from different regions of the world."
I find the wines from Australia (Shiraz) and Chile (any of them, LOL!) to be really good as of late. Affordable, too and with little political baggage attached. ;)
There are several countries producing very good niche product, but only a handful producing a broad range of quality wine. While many of the vineyards in the world were planted in the 19th century colonial periods, interest in making them competitive has largely only happened in the last decade or two. It takes many decades to develop a really strong wine industry that can consistently produce top quality. The US, like France, has been doing this for a long time which has given both countries an advantage.
That said, the US produces some of the very best examples of multiple popular varietals, making it a bit of a wine juggernaut. Very few countries are producing typical and consistent high quality at the moment, though given a decade or two many more will, particularly for niche varietals. I personally tend to pick specific regions for specific varietals (e.g. for pinot noir I look at Oregon, for malbec I look at Argentina, etc.) but am always trying different varietals from new regions looking for a brilliant niche as yet undiscovered.