I'm curious--does this imply internal-politics problems (e.g. getting other departments to expose, and possibly backport, APIs that Chakra needs to consume to do the features), or just weird engineering challenges specific to the Chakra codebase?
I could see some conflicts of interest issues too. (e.g. implementing WebRTC could be against their interests - since Microsoft owns Skype, they might not want to lower the barrier of entry to a competitor.)
In the past when they've spoken about why they delayed implementation it was often due to security issues (e.g. Webgl) or due to the standards proposal not being mature enough and them being worried that supporting it would lock in a bad version of the spec because people would build code on top.
