I suspect the celluloid would be fine if the razor was used all the time -- no accumulation of corrosive gas. Sadly, most vintage straights have been sitting in mostly closed containers for decades, hence the damage.
I will be replacing scales on a lot of razors - either they are broken or badly warped. Easy enough to make and I'm an accumulator, not a collector, so I don't really care about "original" condition that much.
Too bad that razor is now a collector's item -- too many pits near the edge to ever get it really sharp, I suspect.
Peter