In today's backwards world it's boring old Microsoft that's really sticking its neck out and thinking different.
edit: I should also mention that I am incredibly disappointed that they still haven't added multiple user accounts to the iPad, which feels like a no-brainer and a critical feature.
I don't think that is true necessarily. Firstly, as much as iPad may dominate home use, enterprise is still a territory that it will find incredibly hard to cater to. There are multiple reasons for this; the two most that I think are most important: (1) Lack of backward compatibility with existing code and apps (2) Dependence on Apple's curated marketplace for installing applications
> still being relevant in 20 years.
Now, for personal usage, I think WP7 was nice and WP8 will probably be better. Which means that if they realize a tab, as they are planning to, it will be a product that can at least compete in quality if not quantity or marketplace. But again, this is a problem for NOW. 20 years is a LONG time - I cannot even imagine how computation will look like in 20 years!
Apple doesn't seem to have any qualms about making big breaking changes in OS X though.
But wait, they have revolutionized laptop design, smartphones, and even the all in one desktop. The industry is following them in three different segments.
A good example might be Feynman or Einstein: They both revolutionized physics when younger, and didn't do much afterwards. Doesn't mean they weren't doing good work, it's just not easy to create breakthroughs.