Thing is, I don't use my 2D printer to print books or magazines. I use it to print documents relating to my personal or professional needs, but not things which I might otherwise pay for (I suppose the exception, for some people, would be printed photos and the occasional will). I *could* print books (thanks, Project Gutenberg), but I don't. I buy books. I don't even buy eBooks and print them myself, and even if eBooks were much cheaper, I suspect I still wouldn't. I pay for someone else to print and bind them for me. Suits me fine.
I can see a market for consumer 3D printers with regard to simple products which will require no (or little) assembly once printed, but when it comes to the more complicated products I suspect Future Me will still be more than happy to pay for someone else to do it (and, preferably, deliver it to my door).