Brink,
I did try with the Date column pointing down, but my folders still stay at the top.
Then I noticed something "missing" in your picture. Below the "?" in the upper right corner I have "Arrange by: Folder", with a drop down arrow next to it. You don't have this. So I started looking and the Folders in my Libraries have this. But other Folders do not.
If I open Libraries > Documents > My Documents, I have "Arrange by: Folder" and cannot get the folders to the bottom no matter what.
If I open MyName > My Documents, the "Arrange by: Folder" does not appear and I can sort & arrange & have the folders at the bottom. Just like you show.
Both of the My Documents folders appear to have identical content. But opening up via the Libraries does not let me arrange things the way I want. The "Arrange by: Folder" is affecting things. I can change it to "Arrange by: Date Modified", but then it lists all the individual files that were in the folders. It's thousands of files!
I guess a work around is to not use the Libraries, or maybe limit their use.
Thanks for your picture, it lead to a solution.