Have you actually used default Gnome, or are you just speaking in theory? Opening a new file manager window every time I click on a folder is far from user-friendly or convenient, and it has nothing to do with being a blank slate. Explain how having directories and drives listed to the left and having the ability to go backwards and forwards in the same window is a bad idea. Gnome has always had a history for being stubborn. They'd rather inconvenience the user for the sake of appearing "original". Hence them waiting until approx version 2.10 to add a menu editor because it "wasn't needed".
Your theory is very true, but it doesn't apply in this case.