tablets was a niche, but they where and still are 'unpractical'!
They are unpractical to hold, without a stand almost unusable on the desktop, with a stand less portable and nice for transport, unprotected when they fall, the majority of them are overwhelmingly underpowered; do not have a hardware input device, but focus on a touch screen keyboard taking up 50% of screen space; batteries are very short lived and offer battery for only a few hours, dragging a hardware keyboard and mouse with a tablet just isn't it; they are too large to be fitting in your pocket, yet too small to comfortably read and work on, their 3G networks are overcharged (internet is too expensive, and mainly unnecessary and slow for most people)...
I think the public gets the picture, a tablet is just like MS VISTA, shiny and nice looking, and uncomfortable and not practical!
They had one advantage, they caused CPU's to be manufactured that where even more powerful per watt than before!
Back to netbooks guys!