How do u define the value of a work of art in economic terms?

It contradict both the marxist theory of labour and both the austrian denition of supply and demand.

A piece of art takes more effort to a begginer than the same time when he's a master.
It took me 2 days to make crappy drawing when today I can make a much better drawing in 5 minutes.

So over time, the effort I put into a drawing should less, since is easier to me now.
So by this logic the price of my drawings should be lower, since they take less time and effort to make.
But in reality the older I become, the higher I could charge for them.

Also, the austrian supply and demand doesn't work either.
That would imply that pop radio trash has higher value than a more avant garde piece of jazz, because the demand is higher, then their value should be higher.
But this would mean that shades of gray has an infinite value compared to more skilled writers that are only known in academia, like Lord byron or chaucer.

It's absurd to pretend the demand of a product determines it's economic price.
What value has demand of the product over it's aesthetical value.

It's absurd to think that demand determines the aesthetical value of a product, even if my crappy drawings I made when I was a begginer has less value under the marxist theory than modern drawings of mine, and they have less value under the supply and demand argument, they still have infinite personal value to me and I would never sell them, at any price, while I could easily sell a better drawing I can make today by a lot more price, but the newer drawing has less personal value to me than the older one, even if It has less demand from customers and I see it as a worse drawing than the modern ones.

Which is a contradiction of both definitions.