Ok, glad to have helped you feel good for once, but back to the topic of this thread: What stealing were you talking about (in post #206)?
Do you have a source that it happens or is it just some narrative you like spread?
The point is, whether we like it or not, the concept of which speciffic greater whole we belong to is going to be shifting whether we like it or not. Two thousand years ago, there were no Danes, or Czechs, or what have you - you had your Romans, Egyptians, etc., but almost no of the current nations; and even in the case of Romans, it was more of a status of being a citizen of the Roman Republic/Empire than being an ethnic Roman (which pretty much wasn't a thing anyway).
This way, whether the EU will somehow suddenly make us all exclusively European (for which I am yet to see a tangible proof, considering that EU is actually pretty busy paying all the small nation councils to preserve minority languages and cultures), or not, eventually, there will be no Danes, Czechs, or anything else; there will be new nations that will replace them. It's not a matter of "if", it is a matter of "when".
Talking the "semantic we", or how is it stated in English. Just a linguistic tool, talking "us", as in "the ones who are discussing the issue", and by extension "the ones who might end up having the choice thrust upon", even though BOY I hope we won't end up making the choices in this regard.
What I was talking about was, in general, that "a nation" might actually not be a singular whole; is a Moravian still a Czech? Some say yes, some say no. There are those, however, who feel pretty strongly Moravian and not-Czech (in my case, it can get pretty wild; if we do not consider Moravians as separate, I am one half Czech, three eights Slovak and one eight Polish - if we do, welp... What am I? Even Slavic won't work, as part of my ancestry is in Italy and Switzerland); as their number is not insignificant, techincally speaking, they can be considered to be forming their own nation inside a state named after a different nation. Therefore, if we take the concept of a nation to its logical conclusion and allow all people who feel to belong to certain nation to selfdetermine regardless of what that would actually entail, the end we will end up divided in many, many very small "greater wholes". I do not believe that to be desirable (simply, because it REALLY helps the dīvide et īmpera, which in turn results in the small "greater wholes" have very little impact and will result in their eventual absorption into a different, "larger" "greater whole").
My point was simply, a nation does not require a sovereign state to exist, and an existence of a sovereign state does not imply the existence of a nation. In fact, the concept of a national state, if you take a look at who is actually the most succesful currently, is mostly obsolete - the most succesful countries are not singular nations, but many bound inside a larger entity. That goes even for the US and China - in the US, the people living there are both citizens of the larger federation, and citizens of their state; whether they identify as "American" or, say "Floridan", is completely inconsequential. They can be both, and in almost all cases, are. As for China, there's the major domination by the Han Chinese, however, quite a large number of other nations live there, without being extinguished (and that is saying something, considering we are talking about the PRC). In Russia, you have many smaller states that are often "republics", effectively countries within a country. And do not get me started on India.
All in all. A nation does not require their own exclusive state to exist and flourish. A state does not need to be defined by a sole dominant nation for that, either. You have countries that are quite succesful, without falling into neither of the categories. In order for national identity, whichever we might define that as, to erode, there must be a clear push on its erosion in the first place, and even then, I'll ask the final question.
Why is it so important to actually have one?
Having a national identity will not increase your salary. It will not grant you rights. It will not make you like certain culture. "National identity" is effectively just a brand to further distinguish "us" from "them". I personaly do not feel any different than my friends who live all over the continent, and in some cases, on different continets. All that without feeling "lost" or "the necessity to belong". I have my job, I have my friends, I have people who I can talk about what I like and what I don't. I do not require a "national identity" anywhere in there for me to keep going on. As to why it has to be present is puzzling to me. To paraphrase, I really do not care if my hypothetical car is repaired by Karel, Ivan or Mustafa, as long as the job is done well, and similarly, I do not care if my company (providing financial IT services) sells "our" services to US, UK, Hungary or Romania (and we sell it to all of them and others), as long as it works well and is not used for nefarious purposes.
In the end, we have already branded ourselves "Homo Sapiens Sapiens". I consider that quite enough.