I think you should look into how shady the P2P model of Skype was and how easily super nodes could eavesdrop on other users.

It was also completely unreliable when a large chunk the user base switched to mobile messages won’t send, send out of order, would go into the limbo only to appear X days or even months later and if you were signed into multiple devices you were out of luck since if your desktop would’ve received a message while your mobile didn’t you would never see it on your mobile.

Skype died for many reasons MSFT not continuing with its botnet like network model as it’s a huge liability for them isn’t one of them.