Thank you. It turns out that through my random and haphazard approach to problem investigation, I had actually gone through the steps outlined in the TroubleShooting Guide. (Or not. See update below.)
I have the Non App Store version of 1P, and indeed when Discover Automatically is checked, the /Library/Caches/Metadata/1Password/ is properly located and used. In examining that folder, I see there are only 11 entries, and examining the entries with TextEdit, I can see data corresponding to the 11 entries in the bookmark listing on Alfred's Features/1Password preferences. (I should have noted previously that my bookmarks list was not empty, but only had a very small fraction of my vault.)
So I am going to head over to AgileBits and see how the 1P Metadata can be rebuilt.
*** Update: Grrrrr. Turning off and on "Enable 3rd party app integrations" in 1P is indeed what rebuilds the cache. I thought I had done that at one point but well, to quote Dan Quayle, "A mind is a terrible thing to waste....or something..."
1) Toggled off Enable 1Password Bookmarks in Alfred.
2) Toggled off and then on "Enable 3rd party app integrations" in 1P (I could see the new metadata entries pop up in Finder.)
3) Toggled on Enable 1Password Bookmarks. Voila.
May not have needed to toggle the Enable 1Password Bookmarks, but I wanted to be sure there were no intermediary caches that might foul things up. Thank you for your help on this.
*** Update 2: And just to cap it off, the correct quote is:
What a waste it is to lose one's mind. Or not to have a mind is being very wasteful. How true that is.