My first job after leaving the company I did a sandwich course with still used PDP-11, I think an 11/70 and an 11/73 to run stock and order processing systems for a group of steel processing companies. We still had to run backups onto reels of mag tape. After about a year, we started to migrate to MicroVAX, and, having the least experience with the PDPs , I was tasked to convert the processing software over from the PDP version to VAX/VMS. Happy days (1990 ish)
I don't know what happened to the PDPs, but I was almost scared to touch them with their open cabinets and huge pcbs visible. Very noisy as well.