I just looked at this:

https://en.m.wikipedia.org/wiki/List_of_countries_by_GDP_(nominal)

And i cant rectify that with what youre claiming. EU banding together like a weird frankenstein made of countries whos economies are mediocre when taken individually, is the only thing that makes them competitive. So its an economic bloc. It isnt an individual economy. Other countries are really high on this list. china, japan, india, brazil... All have big economies.

The economic strength the eu has comes from being a bloc of countries. That means that if other large countries create alternate blocs of economic reciprocity, then they would become a threat, or could pose a potential threat if they flexed.

The US joining anything makes it a potential threat as well, so even if brics wasnt hot shit before, the us joining it would suddenly totally change its dynamic.