Agree, and Wikipedia does this e.g. for Wikipedia books [0]. If you render any book as a PDF it will append a ~10pt list of all article contributors.

[0] https://en.wikipedia.org/wiki/Wikipedia:Books

Because the list can be huge. It's not unlikely that the list of contributors is longer than the article.

Storage is cheap, and you can stash the list away somewhere that doesn't interfere with the main content, so what does that matter?

What is the difference between stashing the list away somewhere out of sight and providing a link to the Wikipedia page whose history contains the same information? Particularly since storage is not cheap in every medium (e.g. requiring my one-page flier to attach 3 pages of attributions doesn't make sense) and if you're resorting to a link regardless...

I think linking to the Wikipedia page is perfectly reasonable too. I just don't see what's unreasonable about citing the people who wrote the stuff you're using.

I don't see that the link to Wikipedia is not "citing the people who wrote the stuff you're using". When you cite a scientific paper, you give the primary author (or few) and an "et al.", you don't list out everyone who contributed to the paper - you're still crediting them all and if people care, they can go look up the rest.

OK, I'm not really sure what the relevance of this is.

I was just responding to this: "...am I expected to cite every contributor? That doesn't seem reasonable."

And saying how it sounds pretty reasonable to me. If you say that a Wikipedia link counts as a cite then that just makes it even more reasonable.

I think people are using words sloppily. I think everyone agrees that the information should be available. I'm growing confident no one thinks that every contribution needs to be enumerated in situ, and beginning to suspect that no one thinks they actually need to be enumerated separately from the Wikipedia article (unless there are contributions not represented in the Wikipedia history). At which point, I don't think there's any real disagreement here.

I had interpreted your statement above as "Oh, of course go ahead and include a link to Wikipedia - they deserve credit too - but still redundantly list out every contributor to the Wikipedia page". This is because above, I think with the "...am I expected to cite every contributor? That doesn't seem reasonable." the author had in mind enumeration, not simple reference.

I'm just saying that you should give attribution either directly or in whatever substitute way the authors accept. If Wikipedia lets you just link to the page, great! If they wanted you to list out the contributors, well, do that. If that's an unacceptable burden for your case, don't use it.

I think I agree with that, though I'd personally encourage creators to be sufficiently liberal in acceptance of substitutes to allow lightweight use of massive collaboration.

If you're making a one page flyer with enough copyrighted information from Wikipedia to require onerous attribution, you're doing it wrong.

I don't see that this is the case, at all. A single paragraph that has been edited enough times could be the work of an unbounded number of contributors, since it is always a derivative work of the earlier versions. If that single paragraph, modified for format, makes up the bulk of your flier then you should clearly include attribution somehow.