I am thinking from the way we see rumors of new boards being tested and the way so many released models have such similar hardware that Google actually OKs specific hardware for the ChromeOS devices - which includes the motherboard/processor/ram.
That's just a guess on my part but it would be a reasonable strategy for Google to try and maintain quality control within the product range. Perhaps in response to lessons learned about the wide variety of user experience that came from Android - where the hardware was/is a free-for-all.
That really makes it almost impossible to guarantee updates on a timely basis actually without a whole lot of extra work.
Google would either have to take that extra work upon itself or trust these partners to keep up the pace and not give the ChromeOS ecosystem a black-eye or worse - market confusion.
I'm actually fine with it if that is the case. I hope they start competing on screen quality and other features like back-lit keyboards, etc...
It's actually kind of comforting. I have read only one preliminary article on this Toshiba device and I am completely confident about it's performance just based on other similar hardware. And I have zero worries about hardware irregularities delaying updates for the reasonable future.
Just curious to see about the screen and overall impression of build quality.