I appreciate everyone's feedback on this. As I said in the first post, I have an opinion on the subject, but I was trying not to skew the results right off the bat by arguing for one side or the other. Now that a considerable number of people have voted and addressed issues on both sides, here are my thoughts on the matter.
I am of the opinion that it would be best for the hobby and for history to preserve a digital copy of every schematic ever produced. Something like a digital Riders Guide to pinball drawings. I'm not sure how we'd go about it, but I think it'd be a project worth pursuing. There is, of course, the copyright issue to contend with...
Steve Young and the law firm that owns Gottlieb have the exclusive legal rights to any IP that Gottlieb/Mylstar/Premier created. There is no denying this or faulting PBR for profiting from a licensing deal they had to pay the Gottlieb asset owners for. Now, that being said, I also am not entirely convinced their exclusive ownership is completely clear to every schematic drawing Gottlieb ever produced. Pre-1976 copyright law put considerable burden on the authors of published works to copyright them. To be considered protected by copyright, a published work had to bear a visible copyright notice with a year of publication and the copyright owner's name. If you published a work with no copyright notice, the work automatically entered the public domain. Looking at my own physical schematics from Williams and Gottlieb, I can't find one that bears a copyright notice. They bear the trademark of the manufacturer, but that doesn't provide you with copyright protection. Looking through the published works of art, plastic arts, technical drawings, etc. section of the Copyright Registrations from 1960 to 1970, I couldn't find any examples of any pinball manufacturer registering their work with the copyright office. That doesn't definitively prove it, I freely admit I am not a copyright lawyer, but it is certainly hard to see how a copyright can be claimed on schematics with no affixed copyright notice and no apparent registration with the US copyright office.
Now, after January 1st, 1978, when the law changed to make anything published instantly copyrighted and requiring no renewals or registrations of any kind, then it doesn't matter what they put on the schematics, they belong to Gottlieb or Williams or whomever published them. With those, some kind of deal would have to be struck to preserve them. Or else we have to wait 90+ years for their copyrights to expire and hope Congress doesn't pass any more extensions to the copyright laws.
All the legal loophole stuff aside, I feel like a lot of others in the thread do, that schematics, parts catalogs, and manuals being freely available will only help parts sellers like PBR, Marco, etc. If I can tell you exactly the part I need, with a part number, and maybe even a reference page in the parts catalog, that should speed up the ordering process considerably. If I can use a schematic to fix a game, then I'm more likely to order a slew of parts to make it look nice on top of just working.
Am I too cheap to shell out $15? No, I've paid as much as $50 for hard to find documentation. But if I could use that $15 to buy a part with instead, it'd make more sense to me. We will always have to rely on parts sellers for parts because they are physical, finite things. If I buy the last pop bumper cap or rollover button, it's gone till someone makes more, if they ever do. Paper documentation, though, can be scanned and sold indefinitely, or it can be scanned and shared with everyone, at no physical loss to anyone. You can still sell your physical copy, and people without giant printers available to them will likely still buy them. Buying a piece of metal or plastic that is finite and had to be made at a cost makes more sense to me than buying a piece of paper that could be copied for free.
There is also the matter of instant gratification. If I can download a schematic and start working on a game right now, rather than waiting a week for a manual to come in the mail, that's a big deal to me. With parts, there is no question you will have to wait for a physical thing to arrive. With a schematic, the only barrier to that instant gratification is a lack of a scan or the lack of the rights to make one.
I don't want this to be a bash PBR thread. I buy my parts from Marco, but I suspect many of them are being resold from Steve Young. He has been a force for preservation in the hobby. I'm frankly terrified of the man, thus the reason I order from Marco. But I feel like clutching at schematics like classified information, as has been referenced several times in the thread, is counter-productive. We have a vast Internet of information at our fingertips, but a section of pinball knowledge is shut off in a very antiquated system. Planetary Pinball has the right idea, with their online parts catalogs and allowing IPDB to continue to share Williams schematics.
I know this post is already too long, so I'll leave it at this. I am of the opinion that sharing technical knowledge is inherently good for the world. I think information that was once freely distributed by the manufacturers to anyone who asked for it, should still be freely distributed today. A database of all schematics and manuals, with the blessings of all rights holders, should exist for the benefit of the entire hobby.
Thanks, again, for the cordial discussion of the subject. I know their are impassioned arguments for both sides, and I find, as with most things, that a solution lies somewhere in the middle, despite no one so far selecting the "Maybe" option.