* Microsoft claims they've enabled ads on YouTube videos. How, if they're not using the same technique as Jasmine?
* If they are using the same technique as Jasmine, why is that not enough? Why is Google still saying (or at least Microsoft is claiming that Google is still saying) the entire app must be HTML5?
* If the technique Jasmine uses does, in fact, satisfy Google's "HTML5" requirement, but for some reason Microsoft isn't using it (but somehow is playing ads anyway), why doesn't Microsoft just do it? Embedding a web view into a native app isn't exactly rocket surgery: why do they claim it's technically difficult and time consuming?
Quite a few WP applications that are video-centric (such as the non-MS YouTube apps, Netflix, etc.) use their own much-improved video player. Even Microsoft provides a better video player for usage in WP/W8 applications[2]. Making an improved video player on a per-app basis probably would require a lot less overhead than changing the system-wide video player.
This is all just a guess of course.
[1] http://www.windowsphone.com/en-gb/store/app/youtube/dcbb1ac6..., check the screenshots
You know what? If it is time consuming to implement, it's Microsoft's problem, not anyone else's. Lots of people would be happy to get shitload of money from Microsoft and assemble a team to implement it if their problem is difficulty and they are so generous to be willing to pay cash, as they brag about in their blogpost ("...at Microsoft's expense...").