May not be clear, even to finops at Microsoft. Skype tech ended up in Lync subsequent versions, aka Skype for enterprise. The user base also became a free ad target (to buy the entire consumers tool suite) I remember being constantly nudged to sign up for the free 30 days One Drive to backup Skype pictures and the jazz. So creative these heads of sales at MS.
(notable that three of the four greater fools in your post are Microsoft)