I can see kind of both sides of the argument. Soem years ago Battlesmurf put together with some others a repro of RECCA for the US NES. Now, I would say that it was more as a service to both a decent title and making it available in a market that it was not available for (it was a Japan exclusive as I recall) and also that some people just cannot afford the top dollar prices of the original.
As a collector I want to know what edition we are talking about and I want to know a 100% if it's a repro or the original. I can tell you that with some titles there's a lot of worry that you've bought a counterfeit but paid the rate of the original and for this it's a lucrative a market for the dodgy operator and a mither for collectors.
It has always been an issue though with people trying to rip others off but it has become more widespread. Still, if they mark it as being a repro I don't really see what the issue is provided that they do a good job and don't ask for silly cash for a copy.
And just to make a note: there are people out there who actually collect counterfeits as a sort of curiousity by themselves.
So what goes into these cartridges? Is it an Eprom, is the goods on the inside as good as the outside?
A decent repro will have some kind of GAL/PROM but that would be high-end. The proverbial 'back-street operator' will use EPROMs and what's more you have no idea how old the EPROM will be or how the integrity of the Image written to the chip will be once written. As such, you want to know exactly how it was put together. Labels are easy for anyone these days to have produced and to a high standard. Manuals require more effort to manufacture a convincingly good faximile of the original and some take the opportunity to make their own design and take on the original in some way or other. Boxes are easier to produce than manuals. But it is still a question of numbers: just how many they intend to sell and how many sell kind of dictates their methods and the options open to them unless of course they happen to have access to a printers, fab, etc. that is
There's no way a repro/bootleg will ever be able to perfectly replicate the original PCBs to the point where you can't tell the difference.
I guess it would be technically possible, but it would take excessive effort, and be more expensive that what's worth.
That's showing some fetishistic tendencies there I'm afraid

For the PCB, it may be that the quality can be matched and improved as fabrication processes have improved over the interim of the 80s to today. It only matters to people obsessed with minutae I would suppose. I am interested to know chip numbers and such like but I have a mind for that sort of thing. But it doesn't detract from the 'product' so to speak. You are not speaking as an Engineer or technical person relying on such statements without some understanding of the technology and manufacture. There are very few processes that cannot be replicated and indeed actioned and if anything we can do a lot more these days than we could 20+ years ago.