MJC wrote:

I'm sure a vertical turntable was marketed decades ago. I don't remember
the supposed advantage, though...

I still own and use one, a Mitsubishi LT-5V.

The main advantage to it, it's practically immune to rumble via outside
sources. Within reason, stick it on a wobbly table with a loose floor, jump
up and down while it's playing and, nothing.

It's not the greatest turntable ever built for other things (besides looks)
but it is good at that one thing. Up and down vibrations just don't bother
it.

-bruce