This probably depends on how arcane your research topic is. There are sources out there that have not been digitized, and this may require one to go hunting for

This probably depends on how arcane your research topic is. There are sources out there that have not been digitized, and this may require one to go hunting for some old, dusty tome. But this is all part of the evolution of how we get our information. More and more, I expect to see newer books go straight to digital formats, with dead-tree versions becoming a bit like vinyl records. Used book stores will sell things that are out of print, and things that were never converted into a digital format. Edit: I forgot to mention that some libraries already offer borrowing of eBooks. So some of them have seen the direction of things, and instead of resisting, are adapting.