Are we sure?
It looks very much to me that putting RT on a tablet means they're aiming not so much at the hardware or the software, but as acting as a controlling retail channel. That's where the money is. That and subscription models. If, for comparatively little effort, you can lock in customers to an ecosystem and take a cut of everything they do in it, you can mine the hardware/software dependence without ever having to do anything new. Very much like Apple did with the graphic design community and their frightfully expensive font libraries.
Ten years ago, that would have seemed laughably arrogant, and wouldn't have stood a chance in the retail environment. After the collapse of so many content empires, music stores and the DRM ruckus, expecting people to cede control over their own computers just so they could be more efficiently fleeced would have been as insane an idea as selling "thin clients" to consumers. Or 'push media', for that matter. Back then, computers were tools for enabling creativity and innovation as much as for flogging it. Linux was offering a genuinely open, in all senses, alternative to the proprietary restrictions of monopolists, and a new generation was growing up with computers, unfazed by complexity and jargon, who would engineer innovative solutions, turn data into knowledge and forge a bold, new, meritocratic economy.
It hasn't turned out like that, sadly. Instead, it's turned into a meretricious, ad-spattered, proprietary soup of electronic soma, served up via pointlessly expensive, and mostly useless, devices. Walk through any public space, and you'll see a huddled mass of shuffling humanoids, like an ADHD version of Second Life, tweeting gibberish to the void, waiting for some Shoreditch flack to rediscover the knowledge economy.
Perhaps I'm getting old, but if this is the future, I think I'd rather be dead.