Why do we have menus?

We have menus in our user interfaces for two principal reasons:

1. Because screens used to be smaller so that not all of a program's functions could be shown at a time.
2. To reduce visual clutter.

As we started having a little more space, we started having toolbars, but some user interfaces, such as that of Blender, are deemed overwhelming in the amount of functionality that they provide at one glance.
The impression I get is that there is no silver bullet in interface design: toolbars can be useful, but icons are not always clear to decipher - Apple, for instance, introduced the "Show all" button with text in their System Preferences dialogue, apparently because this is easier to understand than any symbol they could come up with.

tags:interface design,menu bar,usability