This is all dancing around the easy and obvious solution that will satisfy all parties involved.
Clearly, the best way to move forward is for WotC to just suck it up and send electronic copies of books to anyone who can probe they purchased a rulebook. It doesn't cost WotC anything because we purchased a book, and PDFs are easy to generate in InDesign, which is used to layout the books anyway.
You just need to scan a receipt and email it to them and they will respond with a DMsGuild code that offers the book with a 100% discount.
Simple and fair.
The only teensy tiny problem is those rare people who haven't kept receipts for purchases for six years. Well, they can easily go to their FLGS or book store with a copy, explain their need, and get a replacement receipt printed out.
I can't imagine any reason a store would refuse this simple, harmless request.
The only complication now is those very rare people whose FLGS has closed in the intervening years. Sadly mine was a casualty of the Great Recession and closed in 2015. (RIP Gamer's Lair)
In that instance, it should be a simple matter to let people take photographs of them holding their book as proof and WotC will give them a free PDF copy.
I think we can all agree this is a fair and reasonable solution to the problem. And easy too. Everyone has a camera.
As an example, here's me holding the
Player's Handbook. This took 10 seconds to capture:
Not hard at all. I can't see any reason why WotC shouldn't give me an ebook for that.
Why, would you look at that. Somehow my preorder of
Theros arrived early.
Can I get an electronic book copy of that too, please?
There. Problem solved forever.