This argument is specious. Bridges only continue to be relevant a thousand years on because humans have barely evolved in that time frame, not because bridge builders put any effort into ensuring their bridges would still be relevant to future mankind.<p>Computer programs on the other hand are driven by fashion, and evolve rapidly. Digital documents created by programs will cease to be readable when the programs that could read those documents fall out of fashion, but this is not due to any short-sightedness by the developers of these programs, but rather by users that choose to prefer new (more fashionable) programs even when these are incapable of reading the documents they previously wrote.