Tablets could hardly be considered consumer appliances before the iPad. They're not even in the same league, and this is coming from someone who owns zero Apple hardware.
I think tablets before the iPad would have taken whatever they could get, but they couldn't make it in any market. Apple had to wait for many planets to align before they could make their move:
- It wasn't until the web that any new consumer computing platform was viable whatsoever.
- Even then, the new platform had to start as a phone, so people had an excuse to buy it (well, I need a phone anyway...) and so the carriers could subsidize it.
- All the technology needed to be there, and cheap: a responsive multitouch sensor, a GPU for smooth interface animation, a backlit color screen, gigs of solid state storage, hardware video codecs, batteries that last for days, durable glass/metal enclosure, and probably all sorts of little things that we don't even notice.
My point is that the iPad's success wasn't about being first. It was essentially about being last.
Don't forgetting that there were touch devices prior to it, but those needed a stylus. Of course you could touch the screen for response, but those were not designed for such use.
Jobs success was in understanding that the first thing you needed to do to make tablets popular was to throw out the stylus.
