Chromebook won't fail. How? Why? Too many "thought" leaders consider it a good device, and in turn, a lot of normal people will buy into Chrome OS. At the end of the day it is a cheap computer that will get the basics done, and given the mounting pressures on consumers in terms of employment and other issues (e.g. dependability on Google services), Chrome OS can succeed.
That said, Microsoft can still fight back. As I said earlier, Windows RT is unambiguously superior to Chrome OS in terms of function and, to be very honest, apps and games. In addition to a proper Office suite (2013 today and Gemini tomorrow), RT has a growing catalogue of apps and games, especially from Gameloft, Disney and Citrix.
Of course there are some optimizations needed: Windows RT needs to be adapted for use on non-touch hardware with less RAM and less powerful ARM CPUs. Microsoft cannot afford to see the OS lag, Windows RT needs to be a tier-one quality experience in comparison to the competition. Secondly, the desktop needs to be moulded into an environment that (1) does not lead people into thinking x86/win32 applications could run on RT and (2) allows initially touch-focused apps to work well with mouse and keyboard. Thirdly, RT-powered 'laptops' need to emulate the "thin, light and long-lasting" mantra, i.e. needs to look like a MacBook Air and take the MBA in terms of battery life.
The aforementioned RT 'reference design' for laptops could be a solid contender against Chrome OS. Microsoft can do itself and the OEMs a favour by putting out a core reference platform in terms of minimum hardware specs and general design parameters, and ask them to push RT laptops in the Chromebook price range.
Though to be honest I expect the OEMs to take it and stuff an Intel Baytrail CPU onto these platforms and push them as cheap full-powered PCs. In response Microsoft can be the sole driver of the RT model by putting out a "Lumiabook." This 'Lumiabook' can come in at competitive pricing, a variety and array of colours, some basic subscription starters (1 month Xbox Music, 1 month Skype, etc) and Office Gemini.
Think about it, Microsoft can directly approach 'next-gen' users, start-ups, budget conscious schools/companies with the "Lumiabook."
They can drive using messaging along the lines of, "we took what you knew about Docs and Chrome, and supercharged it with the features and power you need to thrive....enterprise apps, security, business class cloud integration and devices that speak to everyone's tastes and personalities. Lumia, your next step."
Pair the book with the Lumia series of phones, tablets and wearables, giving people a true family of devices across different form-factors but tightly integrated, in a true and profound way.
The Surface line can be developed into a series of devices for use by power-users, specialists and professionals in need of additional power and versatility. For example, the 'Surface Pro' could be raised into a device series to take on the MacBook Pro, and the 'Surface' into a line to take on the MacBook Air.