Why would structural editing be a dead end? It has nothing to do with storage format. At least the meaning of the term I am familiar with, is about how you navigate and manipulate semantic units of code, instead of manipulating characters of the code, for example pressing some shortcut keys to invert nesting of AST nodes, or wrap an expression inside another, or change the order of expressions, all at the pressing of a button or key combo. I think you might be referring to something else or a different definition of the term.

I'm referring to UI interfaces that allow you to do structural editing only and usually only store the structural shape of the program (e.g. no whitespace or indentation). I think at this point nobody uses them for programming, it's pretty frustrating to use because it doesn't allow you to do edits that break the semantic text structure too much.

I guess the most used one is styles editor in chrome dev tools and that one is only really useful for small tweaks, even just adding new properties is already pretty frustrating experience.

[edit] otherwise I agree that structural editing a-la IDE shortcuts is useful, I use that a lot.