Not related to the comment, but in general I agree with you.

You can't have a single monetary system without complete unification, including tax systems, budgeting systems, governance models, retirement systems, benefits. I mean, you can, like we have now, but it's not sustainable, and eventually we all have it worse.

As a European, I would not want to go that way, since I'm afraid such a unified EU will be a bureaucratic monster that is even more centralized than the USA, and way more autocratic than any current EU state.

I'd rather take a step back, dissolve much of the EU's competences, and go back to pure trade union, dissolve the EURO as a currency, and let every member state take sovereign decisions on their own.

I recently became much more pro-total-unification, so let me give you this counterpoint: individually, European nations are no match to the major superpowers, neither economically nor militarily. We'll get gutted by divide-and-conquer approach. In contrast, bound much closer together (particularly with some form of pan-european armed forces), the EU would become a proper global superpower and a counterbalance for the USA and China.