Dave Michels has it pretty well nailed..No, this isn't MSFT. This is pure Skype. All the way. For once, you can blame Microsoft.
Here is Skype’s official comment regarding Skype for Asterisk, according to Jennifer Caukin, the current spokesperson for Skype.
“Skype made the decision to retire Skype for Asterisk several months ago, as we have prioritized our focus around implementing the IETF SIP standard in our Skype Connect solution. SIP enjoys the broadest support of any of the available signaling alternatives by business communications equipment vendors, including Digium. By supporting SIP in favor of alternatives, we maximize our resources and continue to reinforce our commitment to delivering Skype on key platforms where we can meet the broadest customer demand.”