Why did both the National Portrait Gallery in London and the State Tretyakov Gallery in Moscow decide to change their exbitions?

• The National Portrait Gallery and the State Tretyakov Gallery were competing each other to be the best world's gallery

• The National Portrait Gallery and the State Tretyakov Gallery were changing their expositions because of their commercial purposes

• The National Portrait Gallery and the State Tretyakov Gallery were marking their 160th anniversaries by loaning treasures