Hrmmm... interesting logic.
The one area I think this argument is wonky, is the idea that the Nook is as useless without B&N as the Kindle would be without Amazon.
Shoot me if I'm wrong, but I think that without Amazon, books for the Kindle would fast become hard to come by. Sure, .mobi formatted ebooks are available elsewhere, but would new bestsellers be made available in .mobi format if Amazon weren't around? I don't think so. Whereas the Nook, to my understanding, supports more formats, and ones more likely to be available with or without B&N. So the wireless functionality might be completely useless (likewise the Kindle's if Amazon goes splat), but the basic 'displaying books' functionality is more resilient.
Now, my disclaimer: I don't own an ebook reader, I'm NOT in the USA (hence the whole wireless thing doesn't thrill me), and I'm just a little biased against Amazon