Also worth mentioning: you "cheat entropy" by building for the web in the first place. All my old Android apps started getting broken by Google changes after about five years. Imagine if a five-year-old web page just stopped working due to a browser update.
@nolan uhh, we're there now. everything, even simple noninteractive pages, is a javascript mess, pulling in deps from third-party hosts that won't exist in 5 years.