I think that developers _should_ think about how they licence their software. Software licences are a cornerstone of the free software movement, and people should really consider what they believe people should have the right to do with their code.
Software licenses are a cornerstone of the free software movement because they are our only defense against copyright.
I agree that we need to keep thinking about what one person has the right to do with another person's code, but copyright is a terrible starting point for that thought process, centering as it does the business models of eighteenth-century stationers at the expense of the much broader interests of political dissidents, scientists, historians, patients dependent on medical devices, teachers, students, librarians, archivists, whistleblowers, anybody trying to fix broken things, tinkerers, and journalists.
