As much as I appreciate Wayback Machine, it's the responsibility of authors to choose an authoring format that can stand the test of time, at least for content you care about. HTML is built on a rich foundation of markup languages which is more than adequate for preservation. Just that it renders in a browser isn't good enough as browsers have turned into overly complex monstrosities with a high risk of loosing further browser code bases going forward (eg. Moz loosing their Google deal, and developing browsers becoming economically infeasible) at which point we're at the mercy of an ad company to even read our documents.