Will the EU‘s fourth freedom be further challenged by present members of the single market?

The creation of a single market in Europe, conceived as the application of the so-called four freedoms (goods, services, capital and manpower) of movement was in vogue in the 1990s. What has happened to this dream? At the time not only business communities but also consumer associations, and even labour unions were all in favour of opening their national economies to the winds of continental competition. Three decades after, some national communities seem to have turned their backs on the free movement of people. The case of Eastern European immigrants settling for work in the UK after 2004 comes to mind, something which arguably was one of the main reasons for the Brexit vote in 2016. The issue could again become the focus of populist governments or parties (e.g., in Italy, France, Sweden, Austria, Hungary or The Netherlands), should the danger of an EU-wide recession or an idiosyncratic crisis in one of the poorest member states (MSs) materialize. Actually, a new intensification of intra-EU migration flows could be one of the outcomes of the unravelling of supply chains as a result of the COVID epidemic and geopolitical considerations, such as the EU's wish to diminish trade dependence from China and Russia. The ground is slowly eroding under the feet of those adamant to cling to the free movement of people as part of the acquis. The EU Commission should give thought, before it is too late, about the fourth freedom particularly in view of future EU enlargements.