I remember ThinkPad docking stations that could have a discrete GPU in the dock.

Well remembered! But in that case, the external graphics card was used to drive a separate external monitor, not the ThinkPad's LCD.

That doesn't count and you know it; that's an external PCI express device, isn't actually part of the product itself.

Microsoft's statement is accurate when talking about a single product.

See comments just below. You've been able to use external graphics cards with Windows for ages, and it was a feature of ThinkPad docks back in 2007 or so, if not before.

And you're still missing the point. Microsoft's claim was about a single, integrated product.

So let me simplify:

  1) ThinkPad docks are an *optional accessory* that are
     not an *integrated* part of the product.

  2) the top part of the Surface Book doesn't have USB or
     display ports.  You can't buy it without the bottom
     part.

  3) Windows 10 is the first version of Windows to support
     the necessary, seamless multiadapter support they
     needed to allow seamless transitioning between the
     integrated GPU and the discrete GPU

Other products have had bits and pieces of almost everything in the Surace Book (none of them had the changes present in Windows 10, obviously); what Microsoft presented is the first fully-integrated representation of that technology today, that I am personally aware of. If you can show another laptop, that out of the box, in its base, has a GPU, and a detachable screen, I'm sure we'd all like to see it. Microsoft's claims are very specific.

Microsoft had some very specific, contextual qualifications to their statement. Since we're being pedantic, I though it was important to note the subtle distinctions.

Er.. I'm not arguing with you. I understand it perfectly well. Please see my other comments in the thread....