"Also, in my experience, every company thinks they are unique and that they have special requirements, but they're not."
That's your experience. Others have other experiences.
I had a client in logistics, mostly print logistics and, true enough, that cold be run on an ordinary ERP system. But they also had a few outstations doing reprographics and it turned out that actual print management had a quite different approach. They had a different package just for those. Moved to another client, also in print, and they had a separate print-industry package, basically similar in scope to the previous client but from a different vendor.
OK, so the print job management task is fairly standardised, just different to ordinary order processing/warehousing etc. but still able to be served by standard packages, just don't expect your ERP approach to work without a lot of changes.
Moral 1: there may be scope for ERP packages but their nature can vary between
But client 1 had a contract which required custom printing for which client 2 was sub-contracted. To get the required data in from the customer and then from 1 to 2 required a certain amount of customisation of the ERP system, some from the vendor, some from me. And when the data got to client 2 it was handled by entirely custom software. In fact at client 2 apart from what was, essentially front office functions handled b the bought in package all the production S/W was custom. And none of the custom production print S/W would have been in the least applicable to the ice cream factory gig...
Moral 2: production control is likely to be custom.