People still sculpt. Go look up Bobby Fingers on YouTube to get an idea of what sculpting looks like.
There are a variety of clays. From what I hear, most sculptors use some form of air-dry, not firing clay like pottery would use.
Nobody ever sculpted in marble. You would sculpt in clay, make a plaster mold, fine-tune the design, then meticulously transfer it to marble.
They are trans.