To be honest, it is a feature that a tablet was supposed to support. Microsoft is just trying its best to maximize the possibilities of a tablet, while Apple to maximize its profit but undermining the capabilities of their iPads.
And this is just one of the features that truly make a tablet a productive device. In terms of functionality and productivity, iPad still has a long way to catch up with Windows tablets. And the intrinsic framework of iOS has quite many limitations for iPad to be as powerful as Windows, unless Apple makes a big structural change to iOS (i.e. supports a file system, supports external storage, supports mouse & stylus, etc) or even allows iPad to run MacOS (which I think Apple will never do this, because it will hurt their MacBook sales a lot).
Ding Ding Ding! You win!
Seriously, though, spot on. It's a difference in how Apple and Microsoft conduct business right now.
Apple, on the one hand, wants you full-on into their ecosystem. Each product for a separate use, and you need all products to make use of everything. More money for them. It's all about cross selling the hardware so you have a Desktop, MacBook, iPad, iPhone, and Apple Watch. One product is not supposed to infringe upon the functionality of another in any real meaningful way. This is how they make money... selling you the multiple types of hardware.
Microsoft, on the other hand, sells you their service. Windows. Office. Skype. Bing. OneDrive. Azure Cloud Services. Microsoft makes a very small portion from their hardware, so they concentrate on Cloud and services. That's where they rake in the money. So it's no problem for Microsoft to sell you a phone that is so powerful it can hook up to a monitor, mouse, and keyboard to replace your laptop and desktop. No problem for Microsoft to sell a phone large enough you don't need a tablet.
It was only when Apple realized they were losing ground in the mobile market that they decided to create an iPhone with a larger screen to compete with the phablets on the market. Samsung was kicking their ... ah... hind quarters in that respect. Apple always stated that no one needed or wanted a phone that big. They didn't want to make it because they knew it would cut into their iPad sales, but the Samsung phablets were already doing just that. They made the iPhone 6+ to keep from becoming irrelevant.
They also have kept the iPad dumbed down to keep it from cutting into MacBook sales. However, again, with the market pushing for higher end tablets and due to Microsoft's success with products like the Surface line, Apple doesn't have any choice but to follow suit and make their offering a bit more powerful.
Apple is just struggling to stay relevant. Are they "currently struggling?" Certainly not by any stretch of the imagination. However, Apple can see the trends and realize that if they don't adapt quickly they will be left behind within the next 5 years.
Something like Windows 10 with Continuum on a phone is something that flies in the face of everything Apple has accomplished by keeping different types of hardware separated. Apple must adapt, and I'm sure they are working on doing just that. There is much more planned that has yet to be seen to improve upon the Apple line. Plans to keep them not just afloat, but to try to keep that pristine image of "best quality product" in front of the media for the long run. Notice I stated "image" of best quality product, not that they are the best quality. Whether or not they are best quality is a matter of opinion for many, one which I do not intend to debate at this time.