Seeing how the entire history of the written word spans mere 10 centuries or so now,
their claim is a nice example of hypothetical conjecture or as we used to say,

"God willin' and the creek don't rise..."

There are many threats to film, the worst to my mind being the rising cost of silver as a commodity...
remember the Hunt brothers?

in 20 years, you won't even be able to read a CD-ROM, cause no one will have the antiquated drive/drivers
needed to read one [forget 5.25" disks, how many still have a floppy reader?]... except a few nerds