There are many other digital archives, and that is how the "single point of failure" problem you envisage is solved. The Internet Archive is AFAIK the biggest,

There are many other digital archives, and that is how the "single point of failure" problem you envisage is solved. The Internet Archive is AFAIK the biggest, and the first - the important thing is for others to continue its good work (many have done this for years) - and not for us to rely too much on it or any other single archiving initiative.