Are you thus postulating that the rock next to me is as conscious as I am?

That's a weird use of the term. Doesn't match how I would define it, but you do you.

Yes but due to its density, it takes millions of years to form a sentence. If you listen closely to trees, they also speak with one another. Mountains do too. We just have the attention span of a gnat.

I’m sure at some cosmic level there’s cities of marbles like ours just humming away.

Panpsychism.

https://en.wikipedia.org/wiki/Panpsychism

I think it's a bit kooky, but there are weirder things that are true in this little Universe.