Yes, of course, the perpetual and unlimited funding of something that is failing is unsustainable either at individual country level or at the EU level. However in the case of e.g. Steel, where the downturn in the Chinese economy had led for a time to China dumping large amounts of cheap steel on the worlds markets and thereby making many otherwise efficient steel making plants unviable, a short term plan to fund in our case UK steel plants through such difficulties is, or would be acceptable, at least within the community concerned, because they know that once something like steel-making stops, it virtually stops for ever.
Many countries in the EU do fund, or state aid, their own industries or company's but they do it under cover, its less honest, but it keeps the local politico's in favour with their electorate. Again other countries in the EU don't have the guile, or the inclination to 'cheat' and so they and their people suffer.