I disagree with this view, competitions make countries specialized and become efficient.
Yes and our competitors are in India, China and USA. EU counties spend half the money USA spends for army but our strength is not even 30% of USA. Simply because every country develops own weapons. In USA Utah dont make own fighter jets and Florida their own. They focus resources in one place.
We need to understand Euroep was a continent of constant wars for 1000 years. Most countries was constantly in war. When they end one they started new. Only in last century after EU was formed that changed. We need patience and Europe will achieve great things.
And in that case, Brexit can be proven to be working well for Britain as the country will not anymore be dragged by the weakness of Euro
UK never used Euro. UK uses GBP. They were never really part of EU. It was the last time for them to decide if they want to be in or out. Being a bit in and a bit out was dragging EU back for decade.
Does that mean that countries which did not accept EUR are not really a part of the EU? If it's so, there's a lot more countries like that within the EU.
No it simply means that countries that dont use Euro cant be dragged by the weakness of Euro. They have their own currency and can manipulate it anyway they want.