I would certainly dispute any idea that the ribbon is more intuitive. When looking for a function that you don't frequently use, you must guess what an icon for it might look like, which tab it may be under, then scour that tab for it. You must also be aware that the button may shrink, move, or disappear the next time you are looking for it if the window size has changed at all. It is much easier to find this type of function under a traditional menu using words, even if it isn't as pretty.
Besides all of that, you are assuming that initial learning curve is the most important thing. Most people don't buy office just so that they can use if a few times, it can generally be assumed that they will use it consistently for some time. The traditional (pre-ribbon) interface allowed users to choose exactly which tasks they use frequently and choose where to place the appropriate toolbar for that task. All of the toolbars that you selected would then be available at all times, not hidden in multiple tabs. This allows users to optimize their own version of office over time so that they always have their most common tools close at hand. With the new ribbon interface, you are just stuck with a one-size-fits-all layout.