I think the idea of the Window Chrome "getting out of the way" of the user is a good concept, but we fail to consider what the user expects at arms length. We also have to consider the chicken-or-egg problem

In the example, we have a sidebar for the formatting in the newer example vs havign that in the toolbar in Lion. Was it that back then, people were more likely to configure fonts & formatting settings, and we've gradually as a society de-emphasized our formatting in word processing? Or did UI changes such as this, hiding formatting options push us towards a world where we care less about formatting? I'd like to think it's a bit of both; as the user-based broadened, you had less percentage-based people that cared so heavily about formatting, so UI changes were made to optimize for that, further pushing people in that direction.

On a different note, I want to call out just how badly the sidebar is laid out compared to the toolbar. In the Lion toolbar, there were unlabeled sections but it was pretty clear what the purpose of each group was. Then you have the sidebar, where labels are added in some places, excessive space given where uneccesary, tabs that are sectioned off from the settings they'll show/hide, collapsible sections that can also be shown/hidden, some dropdowns using up/down caret while others just use the down caret, most dropdown carets being right-aligned but not the gear one, and in the liquid glass versions, the overlay of toolbar buttons over the sidebar creating confusion.