After publishing his work, researcher earns only the citation. His work can be the start of a new idea or new set up ... with the pass of years researcher don't earn a lot. Why don't find a new system where a researcher can earn from his publications (percent of publication cost) that can encourage the researcher to progress in the publishing. It's question of continuity of process. Why the commercial societies can earn from our work along time, however, we can't earn from it.