While pointing to the rise of Microsoft Teams as a contributory factor due to Microsoft's internal decisions, both Wired and Om missed one of the key contributors to SKYPE's demise; that's also the reason why Microsoft put its bets on Teams while letting SKYPE wither in the wind.
Before Slack, for many workers, SKYPE was the way they messaged one another, and people outside their organization. It allowed them to text, share files and advance to a call, then a video call and even a group video call. But as Slack took chat and file-sharing traffic over, offered deeper integration with Google Drive, DropBox, Box, as the ability to start a call with a few keystrokes with many calling and conferencing services, the use of Skype for calls became less and less necessary.
Slack's rise was contributing to less use of Skype in business. And in essence, Microsoft's own efforts to counter Slack with Teams took away efforts to keep Skype alive.
Combine that with what Om said about Microsoft and the phrase "muck it up," and you had the perfect storm. As the Covid-19 pandemic arrived and more people started to need to "see" one another, ZOOM swept in with a well-timed PR campaign. ZOOM's integration with Slack isn't a "Johnny come lately" move either that arrived at the start of Covid-19, like Houseparty's rapid ascent or the repositioning of Hangouts to Meet by Google. Those are playing catch up. ZOOM has had a longstanding integration with SLACK. And, that "love affair" was already blooming. Many Slack users were already ZOOMing, just as they also have been using UberConference or Go To Meeting the same way for many years.
While Skype has the same Slack integration , Zoom kept working and deepening the Slack relationship, and with shared channels that allowed people to work across organizations available, just like Skype, they offered users more integration.
Right now, Slack plus Zoom is winning the battle. If Teams can succeed in moving business over from Slack, then Zoom has to worry about the ground it gained shifting to Teams.