[Existenceblinks]

You know it well (DOM, Retained | Immediate). There's nothing to do with saving react here. Talking about browser app specially, I'd keep eye on standard like Template Instantiation and the coming up Symbol as Map's key. It's closed to the recent "Signal (reactivity)" trend. A way to update part of tree more efficiently without re-render-the-whole-thing. As long as we still use DOM, it's not going to be more revolutionary than this.

[atom_arranger]

The only possible Revolution I see is not using the DOM. JS + WASM is fast enough, the DOM is not fast enough, or good enough, enough here meaning enough for creating highly dynamic 60FPS experiences. Main issue with leaving it behind is A11Y though.