The result is the same when comparing nightly builds. Actually IE updates each month now. Previously only critical updates were included on “patch Tuesdays”, but now features are added too. That is not to say that these particular features will be included in monthly updates to the stable version of IE11.
The VMs are not going anywhere. This is an additional service for those that can’t or don’t want to use virtual machines, or find this more convenient.
The data from the links above is pulled in from Google‘s ChromeStatus site.
Also IE is updated regularly now. Feature updates are often included in patch Tuesday updates, such as big upgrades to WebGL and WebDriver support. As features are implemented (see in development in the links above) they're evaluated to see if they will be included in IE11 updates.
Windows Phone 8.1 Update is final yet. It is in developer preview. You can get the preview right now by registering as a developer and downloading the Windows Phone for Developers preview app. See https://dev.windows.com/en-us/develop/phone-updates
There are only 13 features listed there not currently supported in IE and supported by Chrome, Safari, and Firefox. Of those, 4 are currently in development.
Object RTC is developed by a community group at the W3C. It includes people from Google, Microsoft and a number of telecom companies, amongst others http://www.w3.org/community/ortc/
Even if IE11 has only “almost caught up”, that means, as you point out, that inertia to change will mean existing users will be less likely to switch away from IE, as alternative browsers will no longer be significantly better. Just that will help to halt any downward spiral.
Note that on Akamai[0] (who have many of the world‘s largest sites as their customers) IE’s share is relatively static. On NetMarketShare[1], IE’s share is increasing. It seems any such downward spirals has already halted. At least on two of the major analytics sites that release public data.
Many people use conditional comments, but I wouldn’t go as far as saying most use them. There are tons of browser sniffing scripts out there on the web. I used to have to deal with them all the time when doing web site compatibility for Opera. They wouldn’t have made this change if they didn’t need to.
It is the same situation with hiding support for things like document.all, so they avoid the sniffers that do: if (document.all) { ie = true; } then use the ie variable to give those browsers the legacy IE code path.
EME, MSE, and Web Crypto are very new specifications. They’re just starting to be rolled out in browsers. They’re not going to be rolled out everywhere overnight.
H.264 video codec is on pretty much every major browser now, including Firefox. This wasn’t the case when browsers first supported the video element. It is a similar situation to EME and friends today. Including the potential licensing fee (I assume vendors have to licence the DRM module to plug into EME or get it from the underlying OS in the same way to how they have to licence H.264, but I'm not sure about this area)