I'm not entirely convinced by his claims...
To quote that 100% reliable font of all knowledge, Wikipedia...
https://en.wikipedia.org/wiki/IPad#History
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Apple re-entered the mobile-computing markets in 2007 with the iPhone. Smaller than the iPad, but featuring a camera and mobile phone, it pioneered the multi-touch finger-sensitive touchscreen interface of Apple's iOS mobile operating system. By late 2009, the iPad's release had been rumored for several years. Such speculation mostly talked about "Apple's tablet"; specific names included iTablet and iSlate.
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If Microsoft were really completely blindsided by what Apple produced, then there should have been a full housecleaning of their strategists and espiona^H research agents.
Also....
> It was priced starting at $499, low for Apple hardware
It was still relatively expensive. For instance:
* Netbook: ASUS Eee PC 1005HA (1GB ram, Win XP, 160GB HDD) - launched in 2009 with MSRP of $389.99
* Laptop: Lenovo Thinkpad L412 (2GB, Win 7, 160GB HDD) - launched in 2010 with a MSRP of $599
* iPhone 4: released in 2010 with a MSRP of $199 (16GB) or $299 (32GB) - the same pricing as per the iPhone 3GS, released in 2009
Obviously, I've just pulled a couple of easy-to-find numbers off the interwebs, but the iPad was at the lower end of laptop price ranges at the time, and pretty much double the cost of an iPhone.
> Jobs dismissed Netbooks as "slow... low quality... just cheap laptops." History has proved him correct
I won't argue this one (much) - but at the same time, I'd note that they showed there was a demand for smaller, low-powered devices with limited capabilities. I'd be highly surprised if Apple didn't study this phenomena and factor it into their decision to launch the iPad
> Sinofsky said, "what it did, it did so much better. Not only did people prefer it but they changed what they did in order to use it
Did they? Really? Any citations for that?
iPad sales peaked in 2013, just three years after release, which is around the time iOS and Android devices started to hit the sweet spot in terms of processing power, capabilities and form factor, not least when it came to screen size. It's perhaps telling that Apple finally launched a 4.7" display in 2014 on the iPhone 6, to try and compete with Android manufacturers, some of who had already moved towards 6" screens a year or more earlier (e.g. HTC One Max).
If there were any shifts in how people did stuff, it was driven by the evolution of phone technology, not tablets.
Which isn't to say that tablets aren't good at some stuff - I've owned a mix of Android and Apple tablets since 2010, and for my needs (basic social media, reading, iPlayer, etc), they work more than well enough. But their use-cases are limited, and after the initial surge of interest, they've never set the world on fire...