Apple advantages overrated
I don't think content-wise it's looking good for Apple. iBook has limited selection and will likely be blown out of the water by Google Books. iTunes, similarly, is far from complete and will likely be quickly surpassed by YouTube rentals. If you buy from either store, you're permanently stuck with Apple products; no competition ever. And there will be plenty of media companies that will want to cut out Apple as the middle man.
For developers, Apple is not so hot either: an haphazard approval process and restrictive and (arguably) outdated languages and tools. And Apple seems incapable of delivering low-cost devices, meaning that developers betting on Mac are limited to a narrow market of people who can afford $1000+ laptops and $500+ tablets.
Finally, Apple design is far from perfect. Apple has a good out-of-box experience, but in terms of long-term livability, their products can be mediocre. The iPad has an annoying keyboard, messy home screen (hopefully fixed in 4.0 with folders, but we'll see), and other limitations.
I think Google will be doing just fine. I'm looking forward to being able to replace my iPad with an Android tablet.