With all due respect, that notion that 'competition' would be good for consumers, in this specific context of iPad / tablets is laughable. iPad launched at a time when there was nothing like it, and the first iteration was already something extremely robust.
Everything 'tablet' that came after March 2010 has been *failed* attempts to catch up. Including that hypothetical Windows 8 ARM tablet you're placing your hopes on (actually, a Motorola/Google Honeycomb product would be a safer bet, for that matter... but I don't hold my breath about that either).
The iPad was a relatively great and stable product right out of the gate, because iOS had been worked on for several years. The iOS 1 was lacking a lot of things and the competitive pressure from Android Android was a huge factor in getting to where we are now in iOS.
There is no large competition right now, but there will be substantial competition in the future and Apple will need to stay up on there toes to stay ahead of the pack.
Competition is great for us as consumers!
T.