The big publishers have worked very hard to step this being straightforward :(
> You really don’t have PDFs of your own papers?
Absolutely not. Where would I have _legally_ have got them from? (This was 25 years ago) For my first paper, I have a copy of the paper journal for that month, kept as a souvenir.
> Did you leave academia
Yes
> and delete your data?
No!
That makes sense. Sorry if I was a bit incredulous ;-) I've been publishing for about 10 years, so I'm only talking about the current situation. Things might have been quite different before academic publishing was all online, before arXiv, and before having a "personal website" was a thing. If the publishing agreements back in the day already had a clause allowing the author to privately redistribute their paper, I would assume that if you as the author can get the published PDF anywhere (from a former colleague that still has academic access, directly from the publisher, or potentially even from SciHub), you should be free to then forward it to others or put it on your personal website. IANAL, obviously, so don't quote me on whether it violates copyright to get your own papers off SciHub ;-)
Q: Where is an author supposed to _obtain_ the final, "official" journal-approved PDFs in order to republish them?
Unless I head for sci-hub, I don't have any of mine :(