Single Page Applications are a cancer and must be eliminated, and anyone trying to develop a new one should be put down like a rabid animal. All web pages should be possible to use without Javascript. Want reactivity? Go advocate for HTMX to be standardised and implemented in browsers natively.
You can run the entire Windows 7 (32bit) Operating System in less memory than what the single web page "bsky.app" uses when running in a single Chrome browser tab. If you rendered BlueSky threads into PDF documents, those PDF documents would require less memory to display than what "bsky.app" uses.