An opposing view, developed by Frankel and Rose (1997), states that European integration would instead lead to greater intra-industry trade integration and more similar economic structures and business cycles through the convergence of factor endowments and technology and reduced exchange rate variability, which tends to weaken intra-industry trade.
This view even implies that countries could satisfy the optimum currency area properties ex post rather than ex ante (the “endogeneity of OCA” argument).