The biggest single failing of the Chromebooks is the lack of local storage (of any significant size) and provision for offline apps. And here's why:
This past weekend we had a service outage with Comcast, our cable provider. As our cable provider they also provide our Internet service. Everything was down, and not just in our neighborhood. Apparently it was a fairly large outage -- towns within a 15-mile radius of where we live were affected, according to the recorded message I heard when I phoned in to see what was going on. Incidentally, I used my cell phone for that call -- our home phone service is provided by Skype, and without Internet service, there's no phone either.
If I had depended on an always-on service to run a business, I would have been dead in the water during this outage. As in the past, when a utility drops service, the things that you do with that service don't get done. In an ice storm (very common here in the Midwest), you can lose power, phone and cable anytime, sometimes for days at a time. Business must go on, but these events will definitely bring it to a stop.
I like the idea of the Chromebook, but until there's better provision made for dealing with the entire spectrum of possible conditions, I don't think it's a good model for business to rely on.
The Chromebook is just a rehash of the 'thin client' invented by Ellison and McNeely all those years ago when hard drives were expensive, RAM was more so and network speeds (typically 9600 baud) were sufficient for text-based communications.
These technologies have always promised low upfront costs but they have never quite delivered when it came to TCO (total cost of ownership). The Chromebook will be no different for 'paying customers.'
Right off the bat, most American homes are still communicating at 1-3Mbps. Many are still running at DSL speeds (768Kbps) so the network bottleneck is far from addressed.
Of course, there are all of your unanswered questions and it strikes me that the Google Business model (free apps for consumers, paid for by advertisers -- and business customers) is a bit of a house of cards that could collapse quickly were Google to experience an outage like the one Sony recently encountered (and is still suffering from).