Okay but the comparison was about GNOME vs KDE, not "GNOME modified with 5 extensions and tweaks
Yeah each distribution has their own patch set. If you really want to compare you need to start with the most popular, ubuntu and fedora.
Also, most users will want to install third party applications. Your average gamer will likely install Discord and Steam, both of them use a tray icon.
The two examples you gave are definitely not most users. I'd be surprised if it were even 20%. And the tray icon isn't necessary for either of them to work correctly. Most people use the computer to open the browser.