Actually you're wrong. Tablets used full OSes with a UI that was designed for touch, pens AND keyboards. And they were heavy, had poor quality displays and battery life (similar to laptops at the time - so not shocking) less than now.
Some did use modified UIs which were more suitable for touch, but that doesn't matter because every application you had available to you was designed entirely for keyboard and mouse input.
Actually they would've had a lot worse battery life than laptops, and a lot less processing power too.
Newsflash: It's because the technology wasn't available/cheap enough to integrate until more recently.
I'm well aware that the availability and price of technology had to do what those tablets could utilize at the time, but that has little to do with them being able to make an ARM based tablet with a touch based OS. It was possible for one to be made
Even recent x86 tablets still have the same key flaws, look at the Surface Pro for example. It's got an IPS display, an SSD, a decent ULV CPU, which is all good... but it still is expensive, heavy and has poor battery life. And this will always be true when compared to an ARM based tablet. And apps are still designed for keyboard and mouse input, not touch, although Microsoft is trying to change that with their app store.
One would also argue that Apple ENTERED the competition. It didn't take other companies 8 months to ENTER a category that already existed.
My .02
You can't enter the competition when there's nothing to compete with. The x86 tablets back then were expensive, and had poor hardware and the iPad on the other hand was much cheaper and had great quality hardware.
The two don't compete at all: x86 tablets were a niche market for those who needed to run Windows applications, and the iPad was for everyone else, for anyone who wanted a content consumption device, and today, it's even good for some content creation.
It took eight months for any competition (meaning an ARM based tablet which can actually compete in the areas where the iPad excels) to come out, and it was another month or two after that before anything decent came out.
If by "Apple made the tablet market what it is today" you mean "made them take off", I'll agree with you. Otherwise, the iPad didn't invent jack squat. It was all out there, albeit it just wasn't selling.
No I mean they made it what it is today. Before the iPad there wasn't even anything decent, yet alone good or great... it was all rubbish -- a combination of poor hardware and software at a horrible price point, that's why none of them were selling. The iPad was just the opposite of that: great hardware and software at a great price point.
Apple didn't invent tablets, they didn't innovate tablets, they marketed them successfully.
There wasn't anything like the iPad before Apple made it. Instead of going with a x86 tablet and a full OS, Apple went with ARM hardware and a touch based OS. They coupled great hardware and software together, and then they sold it at a really great price point.
They didn't invent the tablet, but they did innovate it, and then they marketed it well.