> runes basically infecting the entire codebase
Yeah sadly the stores the author talks about here aren't the right way to do things anymore in modern svelte and they're all-in on Runes.
Stores were a big part of the reason I liked svelte; they were so conceptually simple, extensible with plain JS, and made interop outside of Svelte trivial without the Svelte magic leaking out.
They're still in Svelte, but they mix poorly with runes and are basically unsupported in runes mode. I opened up a bug about store behavior not working like it used to when mixing with runes, and the response was pretty much "yeah we don't expect it to work like that anymore when runes mode is enabled".
I don't even mind the runes I just don't get the impression from the docs that anyone has a clear feeling about how to actually use them e.g. forget the toy examples, suppose an alien has given me clump of minified business logic and we have to make it work.