My wife and I had been Windowsphone users for years. When Windowsphone spiralled into terminal decline we had to change. Initially we both went Android with Nokia devices and used Microsoft Launcher and re-mapped the home key for Cortana. For a variety of reasons I picked up and iPhone 8 Plus recently but she stuck with Android.
News that Cortana is going away left me with choices. Rather than wait for Microsoft to “disappear” the app I removed it from the iphone. Siri is more of a friend now but has limitations for dealing with Microsoft services. My wife faced a choice too. After a chat Cortana disappeared. She also used some Cortana capabilities in the launcher too. Realising this was now pointless the Microsoft launcher was removed. So now the phone is getting very standard Google. She has realised that she can talk to the Google Assistant now.
Of course this is the point about ecosystems. It might well be that one product or service isn’t making a profit. Maybe you can’t make some things pay. However, when companies withdraw products and services the ecosystem looses ubiquity.
It doesn’t really matter to Microsoft because we are not core customers. My workplace is but we are not.