I'd argue that there is one last barrier to these slate based computers (smartphones, tablets) and that is to take these screens and make them sunlight readable

I'd argue that there is one last barrier to these slate based computers (smartphones, tablets) and that is to take these screens and make them sunlight readable (reflective), color, same retina resolution, and same refresh rate. once the screen no longer requires a backlight, and can be readable any place a book can, computers will truly be ubiquitous. as for creation tools on these machines they are beginning to arrive now, and they will become more and more mature as time goes on. hopefully a less controlled ecosystem will win out but that much I dont know I can predict.