Further, there's a gigantic blur now between a "desktop" and a phone or tablet, since desktops are more and more becoming touch enabled, as are laptops. It won't be long before no-touch is in the minority, so it makes no sense whatsoever to design a UI based on today for an OS that has to work for tomorrow and beyond.
This is how Microsoft used to get in trouble. Why should they include a TCP/IP stack when so few people have a network connection... fast forward 6 months or a year and the internet is everywhere and everyone is claiming Microsoft has no vision and can't see where the market is going.
There are third party replacement shells to replace your desktop. There are lots of ways you can customize your system. You're arguing for things you can already do.