Here are some reasons that makes Picasso's paintings so expensive
Picasso is not alive
The first reason behind Picasso's expensive artwork is that he is not alive—No more artwork can be produced
His artwork has a limited number of supply, but it has high demand, so the price of his paintings always goes higher.
Original & Unique Masterpiece
Another reason behind the fancy pricing of Picasso's work is his original & unique style. Other painters & even Picasso himself can't exactly copy or create the artwork more than once.
Art representatives
Art dealers or representatives promote Pablo's work, which brings a lot of attention and interest to his paintings and results in increasing the price of the paintings.
Painting related to his private life
Most of his works are based on his personal life. When people get inspired & become aware about his life events, they even seek to buy his art at exorbitant rates.