I swear I remember there being a 3D spreadsheet on the market back in the early '90s(?), but couldn't find it with a quick web search. So I might be confabulating.

That said, you're right that it can be done with modern spreadsheets. It doesn't even require that much finagling:

https://www.pcworld.com/article/439501/how-to-create-3d-work...

I think I first saw the concept of a 3D spreadsheet in Quattro Pro.

The following link seems to confirm this :

https://www.kstreetstudio.com/science/sams/qpro/concept.html

One of my favorite ideas in this space is Lotus Improv. It lets the user edit and view arbitrary "tensors" and not just 2d or 3d data. The UI/UX is fairly intuitive and I'm sad no one developed the idea further. It's formula system is also very interesting.

Here is a demonstration video I found about it

https://youtu.be/lTko_Pt2ZZg?si=9xtATPq7NU9oqooa

Wow, I've never seen Lotus Improv but so far there's a lot to love.

If you're not aware, excel has something similar to the formula system if you use tables, and in combination with LET and LAMBDA it's also pretty pleasant.

I've got the rest of the video to watch, but thanks for your comment!

Thank you! I am blown away!

Aw, he demos the Windows version - the original NeXTstep version has timeless aesthetics.

https://m.youtube.com/watch?v=rgGmKD87U3M

Another innovative but forgotten piece of “better than spreadsheet” software is Javelin PLUS.

https://archive.org/details/Javelin3_5

An SQL database can be an n-dimensional spreadsheet.

I have not seen that, but you'd probably like Microsoft's SandDance[0].

Try it in your browser: https://microsoft.github.io/SandDance/app/

[0] https://pldb.io/concepts/sanddance.html