I have old PA miles too
I also have a membership number that begins with 4000, and I also still have unused World Pass miles in my DL account. I took a DL international flight shortly after the PA transition, and the service was so bad that I have taken very few other Delta flights since, unless I could earn UA miles, an option which is now gone, as well.
While PA's standards had declined dramatically by '91, I still miss flying them.