Just because the Surface was the first to release such a device doesn't mean Apple won't also release such a device. We have seen this already.. Apple didn't make the first tablet either, that didn't stop them before.
The new Surface looks like a pretty high quality product, even though I would never buy one myself. This is for a multitude of reasons. First, I haven't held one (are they even out yet?) so I do not know about the build quality. Second, I have moved away from using Windows machines, malware and viruses aren't my thing. Third, the reason that product won't find much success is because it is astronomically overpriced. I think it cost, what, over 2 thousand dollars? No one is going to buy that for that type of money. You could buy 2 Macbook Airs, 4 Ipads, etc..
So, I think Apple is going to make such a device, create innovation in the keyboard so it acts and operates like a Macbook keyboard we are all accustomed too, but the device will also be able to operate like a tablet. I think Apple realizes that in order for the tablet market to have sustained success moving forward, they need to be able to incorporate actual productive uses of the device, and not just have it be used for streaming movies and the internet.. Thus, I have a feeling Apple has found a way to make a device in that form-factor, detachable, at a substantially lower price point than the Surface. Make the screen extremely attractive, detachable, and can run Yosemite and you have a winner IMO.