I know people invest their money by buying the copyrights to song titles and collecting on the royalties, just as if they were buying stock. Of course the biggy is Michael Jackson owning the Beatles catalog, all copyright royalties to the Beatles music (prior to the establishment of their own record label, Abbey Road) goes to the self proclaimed king of pop.
So yes, a song can remain in copyrights as long as someone keeps renewing the copyright license. I would assume this holds true in the European countries as well, or all an artist would have to do to avoid paying copyrights is to go to Spain to record their cd.;)