Comment by EvanAnderson

The only surefire method to keep the bits readable is to continue moving them onto new media every few years. Data has a built-in recurring cost. I'd love to see a solution to that problem but I think it's unlikely. It's a least possible, though, that we'll come up with a storage medium with sufficient density and durability that'll it'll be good enough.

I don't even want to think about the hairy issues associated with keeping the bits able to be interpreted. That's a human behavior problem more than a technology problem.