Ill respond honestly even though I did make fun of tankies not realising this is a shitposting community.
The problem with capitalism is the same as with communism. Corruption, Cronyism, Nepotism, Greed and Dishonesty. People preaching for communism point at those things in capitalism and act like communism wont have the exact same bad actors trying to game the system.
No there hasnt been a modern attempt at communism because past versions were such SPECTACULAR failures (admittedly mostly for reasons that arent actually related to the system of governance) that the well is poisoned. If you cant convince people that masks prevent the spread of disease when its a scientifically verifiable fact you arent going to convince them that communism is viable when it has historically speaking always collapsed or morphed into totalitarian capitalism.