Their chat about the limitations of optical memory made me think of Magneto-Optic (MO) memory cells [0] that I read about earlier this year. From what I understood (not an expert - so I'm open to correction) we move away from Von Neumann, to something where memory is a "filter" that light passes through rather than a bucket of data that needs to be moved around.
Overall it’s interesting to me that we can trade a bigger size to get more speed.
[0]: https://www.nature.com/articles/s41566-024-01549-1