Karl Marx

"It's not true communism"
"It was applied badly"
"Yes, but there's poverty in capitalist countries too"
Yet, in 150 years of history, no country has managed to achieve prosperity by applying "true communism."
And no, the next attempt won't go any better.
The reason is simple.
Communism is not a good idea poorly implemented.
Communism is a terrible idea implemented even worse.
Every time we give in to the temptation of building a nation by planning people's lives and managing the economy, we end up constructing a hell.
Unfortunately, the belief that Karl Marx's theories are valid is hard to die. The idea of being able to plan individuals' lives is still universally accepted by rulers.
Some try to implement middle-ground solutions, but the result is always disastrous.