The WHY is because behind these tiny cute menu bar options lies kilometer long Microsoft Word 9x menus and submenus that became increasingly tough to navigate. It was clearly a UI element that was being pushed beyond its limits. This is why ribbons were innovated, combining the menubars and toolbars into one element -- a categorized toolbar with the flexibility of allowing common options to be larger than less common options, helping the eye in finding the most likely tools.

As for ribbons, you said it yourself "It just takes practice, which most of us did."