The reason I don't believe it is because the tablet still doesn't have a basic function. It's not a utility ... it doesn't replace a phone/TV/kitchen appliance. I just don't think it will reach 20% saturation unless the definition of tablet changes to merge with a phone based item.
It still seems like segway ...great technology with no application. It does however have apple behind it and they do produce some products that are essential (phones, PCs, laptops) that could lure customers in.
Just my .02
See, I think this is where you're going wrong. The iPad is merely a different form of computing device which, by virtue of its design, is becoming very popular for doing some things people used to do on their PCs. It does, in that regard, "replace" other things for certain functions.
Think of it this way, the PC as it is today was designed in a pre-internet era. The concept of a TV with a typewriter infront of it as a way of manipulating data is as old as the hills in technology terms. With the growth of digital entertainment and internet use the PC adapted to do these things but it retained all the legacy stuff. It's still the same machine it was - in very fundamental ways - when it was only used by boffins in lab coats and people in offices.
But now, where are we? Many people around the world are using their PCs frequently for nothing more than checking email, looking at videos, going on facebook and playing games. Due to the form factor of the PC these things are not as easy as they might be. Big, clunky, often slow machines that do loads of stuff (including crashing and needing specialist help to sort out!) but aren't suited to sitting on the sofa flicking through photographs. Sure, you need a PC to update and manage the content of your iPad but that's not the issue. People now use their iPads for what iPads are good for and PCs for what PCs are good for. One doesn't replace the other but rather it enhances it.
So, just as you may own a small car for going around town and a big truck for your day job, you can now own an iPad for looking at pictures and reading your email and a PC for all the heavy lifting stuff. This means, in a household where you're always fighting the kids for the PC cause you've got a ton of work to do but they want to watch a video, you can now get them an iPad and you're free to use the big machine.
There is no need for all new classes of product to completely replace an old class. The new class may simply be needed in recognition of the fact that people's use patterns have changed.
A case in point here might be the Mobile Phone. It didn't replace the landline phone (at least not at first!) but came along as an alternative way of keeping in touch when not at home or in the office. It was still a massive success and the uptake, once the tech was good enough, was very rapid.
