> Instagram doesn't require an app.

Instagram was app-only for years, though. It added the web version a long time later

I doubt they will keep it app only. If they want to attract news outlets from twitter they will need to support embedding somehow

threads already have embedding, on web click on share button and there is a "get embed code" button.

Ah OK, I hadn't (still haven't) downloaded the app so presumed it wasn't at all accessible without the app.