Innovation doesn’t necessarily mean that all past functionality needs to be carried over. Actually innovation often means that past technology becomes obsolete and gets replaced with something new.
Gnome used to have optional desktop icons. They removed them.
They removed them because with GNOME Shell those icons no longer made sense. There was no longer a concept of dragging apps from a panel menu to a desktop, instead apps were now pinned from the fullscreen app overview to the dash.
Since the code was no longer used by the default GNOME experience, it became unmaintained and eventually got removed.