Remember your physical desktop. A plane piece of wood with sorted items on it.
When the first GUIs came out, there was a background you soon could chose. But the icons to click and launch applications were sorted in groups, and as soon as you opened the groups, you didn't see the background.
Then Windows 95 came. I am really not a fan of Microsoft, but they realized that people want to see their chosen background behind their icons, and MS managed to find a solution. This was a great improval and the thing how people want to have their desks.
Then Touchscreens appeared. Icons had to become bigger, but instead of migrating Microsoft decided to separate the traditional Desktop and the Touch-Desktop, resulting in chaos.
Meanwhile Ubuntu developed the Unity-"Desktop" with a bar on the left side and an empty desktop. This is what we still have in Ubuntu Touch.
While Ubuntu is back at Gnome, and you can fill the background with icons again, the Ubuntu Touch Desktop is still empty. It can be filled with Applications by pressing that orange button on the leftside down button, but then the background is darkened.
Why don't we
- get rid of that bar on the left side
- make a Desktop with background and icons?
That was and is the best solution, working on Windows 95 - Windows XP and Android.