That's a very interesting observation, and I think you may be right, but that isn't going to happen, especially when 9, and now 10 including Greece' countries are not part of the Eurozone and, with this episode as a salutary lesson, probably never will be. Even those countries supposedly 'obliged' to join when they meet the criteria may consider it a bad idea and find a way to avoid passing certain eligibility tests. That's pretty simple; Sweden's managed it for 12 years.
So,this 'ever closer union' appears to me to be considerably less likely than it did a couple of months ago. The Germans particularly, ably assisted by the Dutch, Finns and Slovaks, the Commission and the ECB have given europeans a glimpse of the authoritarian, anti-democratic future that an expanded union could represent. Even those who have been extremely critical of the Greeks and their economic incompetence and previous duplicitousness will have noted the Troika's fairly blatant coup and thought, "that could happen to us".
They'll also note the complete lack of communitarian spirit amongst the entire EU in relation to the migrant issue. I wonder whether this might prove to be a watershed year in which the 'ever greater union' idea suffered a terminal reverse. I do hope so.