Indeed, the intention of the Single Market was to free individuals and firms, within a market where no distinction would be made on account of nationality or place of establishment. This is why competition policy is enforced at the EU level, so that no firm is protected by its nationality.
By the same token, no firm or individual should be penalised by its country of residence. Yet, firms face very different operating environments across the euro area, which can prevent them from exploiting the advantages of the market. For example, the World Economic Forum ranks Finland third in the world in terms of global competitiveness, whereas Greece is ranked 91st.