That said the examples we see in this booklet aren’t really a case against them not having them. They could simply have made these images years ago when they still had access to higher quality materials. A lot of what we see in this booklet is art we’ve seen before. Yes it’s largely from opening and closing credits but these were likely transferred to higher quality photographs back in the 90s.

As for the actual film source which was an intermediate between the cels and the video we see I’m not convinced these are completely lost to time but it’s really hard to tell. Often some special effects will be done in post on the video itself making it difficult to go back to the film source. This was the case with many of the Star Trek series which have been released on great quality Blu-Ray but which needed their special effects to either be redone or included at a lower quality. Animation doesn’t have effects in the same way that live action does but perhaps when we see certain on screen text, shiny lights or something of the sort this might be the case. I don’t know the specifics of how and when they did all of the effects for Sailor Moon.

Speculation on my part. The official story seems to be that these were somehow lost. These weren’t the 1950 and 60s when people didn’t expect these things to be needed in the future. In the 90s the market for home video products and such were well known so it would have been quite irresponsible to discard those.

All said it’s much cheaper to do a software upconversion than to go back to the film source.