[zeugma]

Lost films are amazingly interesting. So many iconic images are simple worn away. A lot of known, but not seen, items from before the mid 30’s are mostly gone, with the occasional found item. Hitchcock’s first movie, lost except for a few promotional frames.

Yes, but it is absolutely vital to the survival of civilization for copyright to last for almost a century. /sarcasm 

[Tolsti]

Actually, it’s a matter that the film itself was on has turned to dust and nobody bothered to make a copy of it in time. The early 20’s film they used was made out of very volatile materials and didn't last more than a few decades.