Microsoft has been doing their penance for the sins against web developers of the two decades past. The company does not want developers to target specific browsers and opt to include W3C implementations of features if they are available.
Microsoft traditionally fought web standards, forcing developers to implement ActiveX and filters to access advanced features such as opacity. Web developers would program their websites multiple times to account for the… intricacies… of Internet Explorer when compared to virtually every other browser.
Now Google and Apple, rightfully or otherwise (respectively, trollolol), are heavily gaining in popularity. This increase in popularity leads to websites implementing features exclusively for Webkit-based browsers. Internet Explorer is not the browser which gets targeted for advanced effect. If there is Internet Explorer-specific code in sites it is usually workarounds for earlier versions of the browser and only muck up Microsoft's recent standards-compliance by feeding it non-standard junk.
It has been an uphill battle for Microsoft to push users to upgrade their browsers and web developers to upgrade their sites. “modern.IE” is a service which checks for typical incompatibilities and allows for developers to test their site across multiple versions of IE.
Even still, several web technologies are absent in Internet Explorer as they have not been adopted by the W3C. WebGL and WebCL seek to make the web browser into high-performance platform for applications. Microsoft has been vocal about not supporting these Khronos-backed technologies on the grounds of security. Instead of building out web browsers as a cross-platform application platform Microsoft is pushing hard to not get their app marketplace ignored.
I am not sure what Microsoft should fear most: that their app marketplace will be smothered by their competitors, or whether they only manage to win the battle after the war changes theaters. You know what they say, history repeats itself.