There aren't any communist countries, only a handful of states run by communists, who don't even claim to have reached socialism yet.

The problem is the commodity form – goods and services made for their use value and their exchange value. This is a problem in the states run by communists. They don't claim otherwise. Neither does any Marxist.

The world is currently dominated by imperialists. According to Marxists, imperialism is the 'monopoly finance' stage of capitalism, which is what you identify.

In a society that doesn't make commodities or which protects certain goods and services from the logic of commodities, the 'gatekeeping' of art (or any other good or service) wouldn't need to happen.

Art under capitalism, like everything else – food, shelter, clothes, air, water, etc – is commodified. This has awful consequences, which affects every commodity-producing society.

The 'communist countries' have only started on the path to abolish the commodity form. It will take decades to complete, maybe a century or more, and is unlikely to be fully achieved before the world is communist.