What makes art valuable?

Rarity has got to be a big part of it, or else how to account for the fact that this just sold for $2.3 Million.

This was produced in 1617.

To me, it has much the same look as medieval art in that artists did not know how to do perspective or draw the human form.

Italian artists were making art which would make the Mughal work seem laughably rudimentary more than 100 years earlier.

Michelangelo's rendering of the Libyan Sibyl (Sistine Chapel between 1508 and 1512)

Or compare with this painting by da Vinci from 1478