Maybe his Adobe CC vs. 6 'forever license' stopped printing when he upgraded his Mac OS - like mine did.Exactly what do you believe that there is in “new software” from Adobe that is “less and less compatible with older RIP imagesetter combinations?" I know of absolutely no features associated with printing from any Adobe graphic arts applications or even Acrobat to PostScript printers that have been removed or deprecated over the last 20 years! Exactly what do you believe has changed?
So he ends up having to keep an older Mac around just to be able to print from CC or pay monthly forever to Adobe.
I managed on my personal Mac for a bit and then switched to Affinity Serif products.
Not looking back, using MarkzWare to transfer from Adobe INDD and save as PDF which is NATIVE for Affinity.