My guess is that as companies are trying to push 8K TV that 8K disc would come

I can’t see there being another physical format until there is a big leap forward in what goes on the disc, or an emerging very cheap way of producing media.

VHS to DVD was the massive jump to digital.
DVD to BD was a jump in perceivable resolution, colour gamut, and standardisation (remember how films used to get sped up?)
BD to UHDBD was another jump in colour gamut, dynamic range, metadata, and a (perhaps less noticeable) resolution bump.

We’re now kinda at the limit of what the studios put out, however. Many studios still produce at a 2k intermediate. Other than full-fat Atmos, and bumping the bitrate to what a cinema gets, I think it’ll be UHDBD and varying streaming services.

ITT: Why isn’t this image an entire Wikipedia article

2026: BD2 - Blu-ray 2 designed to accommodate the data for the new holographic displays

2036: BD3 - Brain downloads