I had an art teacher who was a sculptor.
He worked in bronze.
His wife was very proud of his work, and when the IRS came by and asked the value of some of the sculptures, she quoted grandiose retail prices.
When her husband got home and found out he had a fit as until sold they are only worth the weight of the material.
I don't know if that would work for paintings, the cost of the frame, canvas, paint etc.
That is exactly true - they are only worth the value of the input costs, if given as a charitable gift, etc.
But for estate calculation ... full retail price, even if nobody will pay it, in a down economy.
“We are from the government, and we are here to help.”
If Da Vinci burned his paintings to avoid his wife losing the house, could we say the government was helpng? Not that my Dad is Da Vinci, but who knows?