User Order History Not showing Up in CP
The Order History is the history of that particular order and not designed to pull in other prior orders from that customer.

You might want to make a feature request if you want to be able to see customer histories in the order view:
https://github.com/craftcms/commerce/issues

....if they're a registered Craft user you can use the email at the top to get to their profile (and thus to that field) of course, but that doesn't not help for guest users.