I didn't claim [4] was the solution. I claimed the problem was solvable. One example of how to improve on [4] is to build into browsers the option of automatically searching archive.org whenever you hit a 404.
https://addons.mozilla.org/en-US/firefox/addon/resurrect-pag...
Of course, the whole point of this article is that centralisation of important resources is risky. Archive.org is an essential resource, and it's really far too important to be at the sole mercy of the of the Internet Archive organisation, well meaning and admirable in every way though they are.