If this forum represents a sample of a disappearing user base, I do not imagine how many people that succeeded on updating to W10M have problems with it. First of all, the changes in UI, most people don't like changes, some functionalities that have disappeared, apps crashing with no reason, overall OS instability. As far as I remember, when I developed an App for Windows Phone 7.5/7.8, when something went wrong with the app, Microsoft notified me through the Developers portal. I wonder what are the native apps reporting to Microsoft when they crash right after they're launched. How bad the ARM implementation of Windows 10 Mobile is developed, why Microsoft have been unable to build a stable experience even among the same devices. As for today I don't trust on any ARM implementation of Windows OneCore because for me, Microsoft have no experience on handling those SoC/Processors, as a result we see a broken mobile platform. (Sorry about my english as I am not a native speaker).