- UWP can certainly be more developed, but how will this look like without the mobile devices section ++ surely it will be much poorer & the work of many developers will be lost
Mobile devices were never the focus of UWP development, it was a beneficial side effect that UWP apps developed for touch screen PCs and tablets could be adapted with minimal effort for mobile devices, so the loss of that section has not had any impact on the work of any developers. I don't believe any developer was stupid enough to develop just for mobile devices.
You have to look it different: you won't select UWP if it isn't applicable for phones. So it is crucial to have phones, tablets, always connected device, on the UWP selection, even Linux and Ndroid not just Windows PC!