You simply do not know if he is objectively wrong. On the basis of 25 years of Euro, what we have observed is that in the eurozone, capital follows productivity, and countries tend to specialise in line with what their factor endowment and national inclination will let them. The Euro is usually "sold" as a miracle solution when it has only really been successful for countries that had a very export oriented string industrial sector, and even then, with mixed results (see Italy). Bulgaria can hope for capital inflows and increase in productivity but should also bear in mind that these factors are highly independent on economies of scale and overall sheer size of of the existing industrial base. Capital outflows and alignment with standard european prices may well be in order. This taking the average population age may be a killer. We'll see.