At this point, if MS does not implement these features then it will fall further behind and lose relevance. There are enough people using non IE browsers, that

At this point, if MS does not implement these features then it will fall further behind and lose relevance. There are enough people using non IE browsers, that one could create a new site leveraging these features and ignore the IE users, or provide a significantly downgraded experience. The thing is, it would not take much to do so. A couple of fun games here and there with some useful apps at a significantly reduced cost and there goes more of IE's market share.