On the one hand, yes, you're right, the EU is more powerful economically as a whole than as individual states. But on the other hand the individual states are a bit less unified than the US or China. So they are a bit more individual in the first place.
EU countries still have:
- their own laws and constitutions
- their own foreign policy, embassies, intelligence services, armies, etc.
- their own taxation; there actually is no EU tax (though there is some pressure to create such a thing)
- their own policies for education, healthcare, social security, taxation, trade, etc.
- their own currency in some cases (e.g. Denmark, Sweden, Poland and many other eastern European countries)
- border disputes like Cyprus, the Balkans (several former Yugoslav countries are members or aspiring to be). And though not part of it, you might count Greenland here as it is Danish with a special status.
As a trade block, the EU is pretty large. And the sphere of influence also includes former soviet states not part of the EU, Turkey, Northern Africa, etc. But it doesn't speak with one voice like the US and China tend to do. Also there is a lot of division on topics like e.g. the Ukraine war, energy, and a lot of other topics.
- its own laws and constitution, search "Constitution of California"
- its own taxation (e.g. sales tax differs between states, just as VAT rates differ between EU countries; Americans pay income tax to their state as well as the federation)
- its own policies for education, healthcare (not sure about social security, and not for trade)
- some US states have border disputes with other states, e.g. Tennessee vs Georgia (Possibly the EU does not, they must be resolved before joining, though I can't find a good article on this).
- the USA as a whole has border disputes with Canada
The EU presents more division on more topics than the USA, but the USA isn't united on e.g. energy policy.
Surprisingly far down: https://en.wikipedia.org/wiki/List_of_first-level_administra...
California, Texas, England, New York, Guangdong, Jiangsu. Both with slightly smaller GDP than Russia, the 11th largest economy.
More interesting is the PPP table where Guangdong is close to California.
It's also the only thing that can work in Europe. Anything smaller would make Europe irrelevant on the global stage, and something much more invasive would erase Europe as we know it.
The current mood in smaller European countries is that even though many are skeptical of French and German influence, our interests align most of the time, especially now that the US has succumbed to fascism and stupidity.
It would be interesting to compare economies of the same scale, regardless of legal status: If you are considering the US and China, maybe you should include the whole of the EU. And if you are looking at Germany, Japan, ... It makes sense to not only include California, but also to split up other countries. I'm curious how high up Guandong or Shanghai would be for example.
The fact that the US and China show up as single countries (and not "continents"/regions) whereas the EU shows up as a bunch of "small" countries is source of a lot of inferiority complex in Europe.