Technically this isn't Skype anymore. Skype management needed a cue from Microsoft.
It is still Skype (well, the private equity firm that owns Skype). The msft deal hasn't gone through yet.
I can only assume that it was decided as part of the sale negotiations. Whether it was Microsoft saying "we want to bring in a new team at the top" or the owners saying "we want to maximise profit" first, who knows.