I think that the basic mistake is to attempt to find a on-size-fits-all-solution (actually making a single product and then convince everyone that it is the "rigth product" for them).
I mean, you know how dinosaurish I am, but the usage paradigm in a business office has not changed much in the last 20 (twenty years) or more, a typical employee will have before him/her a screen, and he/she has to input in it some data, little matters if the object is a business letter, an e-mail or some data in a "vertical" dedicated program, and most of the time what they have before them is nothing but a "thin client" or a terminal to a server.
They won't *need* anything more than a plain video card and display and a keyboard, even the mouse is something mostly unneeded. (just for your interest a few years ago I tested in the same office side by side a good ol' "DOS like" accounting program with it's Windows counterpart and almost everyone that used them was happier about the easyness of the workflow with just the keyboard and a few F keys)
Same goes for another vast category of non-graphical professionals, writers, solicitors, technicians, programmers (of non-graphical apps), etc., etc.
Then there will be the professionals, architects, designers, graphical artists, programmers that need each and every CPU cycle, byte of RAM, pixel number and colour shade, and responsiveness they can get (and even more), AND need a stable OS, a very secure filesystem and backup/redundancy reliable solutions.
Then there are the gamers that need if possible even more juice than the above, but couldn't care the least about secure filesystems, permissions, quotas, etc.
On the other hand, if you are on the move you might actually want to have a portable solution, touch and what not, notwthstanding my dinosaurish approach I bought in 1993 or 1994 a Compaq Concerto, tablet with pen (and keyboard) and found it at the time a perfect business solution on the move.
Then there are the "grandmothers", they have three main uses:
- read/write e-mails to/from their relatives and friends
- watch photos and (lousy videos) of their nephews
- search on the internet something (textual) they may be interested in
And finally there are the kids (the few that are not in the gamers group ), they want multimedia (and very little more), and as long as they can get a lousy video from Youtube in low resolution they are OK.
To name a known competitor, the Ipad is IMHO the perfect thing, though overpowered, for grannies, the perfect thing, though underpowered, for kids, and completely UNLIKE useful to any of the other "profiles".