Would anyone even care about Mona Lisa if the exact same painting was done by a random nobody? It's just a portrait.

Most people no. Then again most people are idiots barely aware of the world they live in, much less culture.

People who actually care about art, if given a chance to see it, yes.

Of course, it being done by Davinci is not some random fact about the painting - as if a painting is a mere artifact.

Da Vinci is maybe only the 5th most interesting thing about the Mona Lisa.