in modern society we tend to agree that Duchamp changed the art world with his piece “Fountain” - simply a urinal signed “R. Mutt”… he didn’t sculpt it himself...

He did (possibly). Sorry.

Duchamp was a sculptor, as well as a painter, and Fountain doesn't match any of the urinals sold at the time, by his named source or other plumbing suppliers. Every example in a gallery is a replica made based on a photo of the original, which he claimed to have lost, and they're all different (the placement and pattern of the drianage holes, the indented ring around the 'foot' of the piece).

Same with In Advance of a Broken Arm and a bunch of his other Readymades - attempts to find an identical, commercially available, object have failed.

There's an argument, outlined here: https://www.toutfait.com/issues/issue_3/Collections/rrs/shearer.htm, the Duchamp either made or excessively modified every object he claimed he bought and displayed unchanged.

Therein lies the problem for art students decades later: because his Readmades were/were based on everyday ephemera, few to no examples of other objects in that category remain for us to compare.

I think he was pointing out how few of us look at the objects around us (especially those, like art critics, whose job it is to observe) - if we were paying attention, would we have noticed that his work wasn't what he claimed? Or maybe it's a case of not noticing the art in the world around us until we put it in the special "art room".

Either way, Duchamp is a fascinating artist and (IMO) a compete troll, and may not be the best example to use to defend generative AI.