The funny thing is that no important member of the EU is interested in a Serbian membership in the EU either. Serbia is poor and politically extremely instable. A sort of European Somalia and therefore uninteresting. BTW- the article is wrong in some regards. Serbia is by far the poorest part of Europe and not Romania or Bulgaria as they write it. The Serbs have the lowest income in Europe (fairly half of the Romanian income). Simply check the CIA-factbook.
I think it is unavoidable that Kosova will be ruled by the native Albanians sooner or later. To my information there is a big buy-out of Serbian land through the Albanians in the moment. The number of remaining Serbs in Kosova is shrinking in a frightening way. Since Serbia has no or only very little military or economic means left I doubt that it can enforce its claims.