I failed in my task. With these frameworks, given enough time, there ends up being a lot of "deprecated boilerplate" code, either directly or via dependencies. E.g. Vue is closely coupled to Webpack, and Webpack deprecated so many things between versions 2 and 4, that there's essentially no mechanical way to migrate the code. One must figure out every detail of the auto-generated Webpack config from version 2 and figure out how to do the same thing in version 4. (I'm looking at you, CommonsChunk and splitchunks!)
Legacy applications from the days of yore didn't "bit-rot" like this.