A Preservative also keeps something to last longer than it would do without it.
As nice and as amazing as the original unaltered film is… If it’s rotten or showing moldy bit’s on it you won’t want to consume it.
It’s not an argument I get it. But how many people want moldy or rotten bits.
Being Marketable is a very important factor also.
The “moldy” and “rotten bits” are things that have been in the film since the beginning so your analogy doesn’t make sense.
What you’re asking for simply has nothing to do with the this project’s goals.
They should get it back to exactly how it was or as close as humanly possible. Then use that version as a basis for future enhanced versions.