Most of the support electronics (i.e. circuit boards) are still necessarily rigid, so a flexible display is kinda limited by that for the present.
Personally, though, I'm not sure I'd want a display that can't stay flat -- if I can roll it up when it's not in use, but get it to be effectively planar when I'm using it that'd be excellent, but the floppiness of a newspaper or magazine is not a 'feature' I particularly value when I'm actually
reading it. I don't even like it when my book pages aren't really flat for that matter.