Sure, it's easy to write out the steps like that, but the devil is in the details. It's not super difficult for a human eye to figure out where the original pix

Sure, it's easy to write out the steps like that, but the devil is in the details. It's not super difficult for a human eye to figure out where the original pixels aught to go, but you just can't take a photograph of a photograph of a screen that was half-toned and printed with an offset printer or whatever they used and grab a clean original pixel matrix out of it with color accurate to even other parts of the image. The closer you get, the mushier it gets. Reducing the resolution using a nearest neighbor or bicubic algorithm would give you a cleaner pixel representation, but it still require a lot of cleanup to get the kind of accuracy he was going for, and inaccuracies would be a lot harder to spot in that context. I've worked on image-processing software for some big digital archival projects, I'm a long-time digital artist, and was a graphic designer having worked in print media. I would set myself a good long chunk of time to get that right and doing it for one single image rather than a necessarily reproducible process would not be close to worth it.