This isn’t something inherent to SPAs, though sadly many (most?) do omit the history api and don’t provide usable URLs nor back/forward navigation.

It's somewhat inherent, as the URL will not change by default and it generally takes an intentional to implement sharable URLs.

"Somewhat inherent" isn't meaningful or correct. The fact is that there is a history API and you can use it to implement history for SPAs. Therefore, lack of history is not inherent to SPAs by definition. Intentionality has nothing to do with it.

I find it bizarre how such a site ended up an SPA. Nothing about it suggests SPA. This could just be a website and would be supported by any web browser, but instead they've implemented a crap custom browser and web in JavaScript.

The map kind of does. It's really nice to just click on different dots and see different cities with no latency or page load. I think the right way to implement this is as an SPA with `history.push` for shareable URLs.

That could easily be done with htmx. No need for an SPA.

Not without latency. Unless you make sure everything's on the edge? But that is way more complicated anyways — now you have two systems to maintain, instead of just a single client-only JS app.

And I can’t zoom on my phone??

Seems to work for parent's link on my iPhone (but not OP's link)