I suspect that this relates to my wish list stuff predominately being out-of-print items that show up on Amazon only as independent sales, if that is the right term.
I don’t think Amazon’s wish list notifies you when previously unavailable items become available. It seems to be set up more like a wedding registry—just a place for you to list things you want for future reference or so that people who want to buy you a gift can see what you want.
Try www.ABE.com
If they can’t find it, it usually can’t be found.