Yeah, the second MS announced their Surface devices, the first thing I thought of was "well, that's every single PC maker now in competition with MS, and MS doesn't play well with others if history is anything to go by"
Got a Dell Venue Pro when it first came out cheap, to have a play. And after a few bios upgrades, 8.1 upgrade, constant windows updates, driver upgrades, it's almost workable. Pick it up, let it install the updates, and in 10minutes or so after powering up and eventually locking onto the local network signal (that the very last update seemed to fix), it's good to go!
And then...
Even skipping the horrendous UI, that's clunky on the small screen, it simply doesn't feel as 'quality' as the Nexus7 I also use. Windows, use it on the laptops/desktops/servers, it works and works well, but for tablets, it's still stuck in that odd twilight of functionality that means it's not perfect for anything.
Ok, there's going to be some sales for people who want to access MS Office files on a tablet? No, I don't think there really will be that many. And if you DID want that functionality, the 'safe' choice is going to be a MS laptop/Surface device.
So I totally get why Win tablet sales are next to non-existent, and why makers of these devices are going to flee the platform and follow the rush to the bottom of other Android maker devices.