The parents of each of these elements have to manually map the state changes, they have to be aware of the internal state of the components, just as I was saying.
Check this out: https://github.com/rtfeldman/elm-spa-example/blob/master/src...
Go to the bottom, see how it manually maps the child events of the feed update? You have to duplicate that code for every single child component. All the other steps I described are there also.
Again, there are lots of counterexamples to what you're claiming. The technique you're saying "must" be done in "every single" case came up a grand total of once in the entire code base: the file you linked to.
This is trivially debunked: here is a 4,000 LoC open-source Elm SPA with small, type-safe reusable views that have state and don't do all this. :P
https://dev.to/rtfeldman/tour-of-an-open-source-elm-spa
Plenty of counterexamples in there.
Here's one. https://github.com/rtfeldman/elm-spa-example/blob/master/src...
Here's another. https://github.com/rtfeldman/elm-spa-example/blob/master/src...
Here's yet another. https://github.com/rtfeldman/elm-spa-example/blob/master/src...