I didn't realise Apple were such visionaries. The tablet form factor had already entered the mainstream thanks to the Kindle (released 2007) and several other manufacturers were working with the format. Apple refined it and certainly accelerated consumer interest with their superslick offering but if you're arguing that tablets would never have happened to this day (as in the Nexus) without the iPad, then I disagree very strongly indeed.
It's impossible to say for sure where tablets would have been by 2013 without the iPad. Even with smartphones it's impossible to guess where they would have been by now without the iPhone, since touch-screen phones already existed when the iPhone came out but they were mostly crap for a number of reasons. It's hard to say how quickly others may have risen to the challenge of putting together a multitouch screen and mobile OS that wasn't annoying and had great developer & user momentum behind it. Have to imagine that others would have got there eventually, and apple accelerated things not by being especially innovative, but by simply making products that consisted of a different set of compromises to those other manufacturers chose at the time.
We can say that a few android tablets that were not very good existed before the iPad, e.g. by the likes of Archos.
And as I suggested at the time, the Nexus 7 was probably a response to a number of things:
Amazon somewhat spoiling Googles entire reason for making Android (to get people using Google services etc).
To try and improve the state of android tablet apps.
Non-Amazon android tablets costing too much money, and not enough of them being sold.
We can also look back at the first 30 or so pages of the first u75 iPad thread to see what people were really thinking at the time. Its a very mixed bag, and no surprises that people like editor were skeptical, although he did wonder if he would look back in 6 months and kick himself for not realising what a soaraway success the iPad was destined to be.
Anyway rather than indulge in the usual arguments I will attempt once again to put all of this stuff not in terms of innovation, but simply different sets of compromises. If we look at the set compromises that arguably were part of the design that made the iPad and the iPhone successes, we can see that some limitations became the accepted norm that helped enable competing products to come to fruition, but others provided room for competitors to differentiate themselves from Apple. Here are some of the most obvious examples:
Limitations mostly accepted and also present in most competing devices:
Lack of Adobe Flash support.
Lack of removable battery.
App Stores.
Not the same versions of apps that we are used to running on desktops etc.
Compromises not so often present in Android etc:
Lack of external storage (usb & memory cards)
Obviously its more complicated than that, with degrees of flexibility in terms of choice of App stores, and Samsung in particular trying to bring back some stuff in some of their niche devices that Apple threw away such as multitasking with more than one app on the screen at once, stylus, etc.
I place no bets as to whether Apple will succeed many years into the future, but I certainly don't think they need to innovate as often as some seem to think they do. They can live with quite a lot of competition and loss of market share, and slow incremental upgrades to product spec. And they set the scene for us all to have lots more decent phones & tablets to choose from by giving these segments a kick up the arse back in the day. Efficient mobile OS, good use of multitouch-screen and App Stores were the solid foundation that we got earlier than we would have done without Apples iOS gamble.
And I do believe that even if Steve Jobs hadn't died, they would have done an iPad mini eventually. Perhaps a little later than they did without Jobs, but when alive he wasn't afraid to contradict himself just a few years later, and I see no reason why it would have been any different with smaller tablets.