Seriously, go use products like Google Hangouts, Slack or Microsoft Teams (Microsofts's surprisingly better clone of Slack) and then tell me that Skype was ruined by integrating with Microsoft's other product base. The closest argument you might be able to make is that Skype could have developed new features or updated its UI and stayed competitive, but that wouldn't give them the competitive edge that it's competitors nearly all had in terms of being backed by major tech companies. Additionally, the major revenue source was Business tier use, which Microsoft dramatically improved by integrating it with their other cloud-based business suite applications.
Microsoft didn't kill Skype, if anything they extended its life expectancy and value in markets that actually paid to use it. It's dead/dying now because better tools have been developed and marketed to replace it. That's just standard product life cycle.