If liberalism and economical freedom have passed so many successful tests in many countries for many years, why do communists keep trying?

My Answer on Quora.

This is an excellent question. I believe it comes down to a several factors.

Source: Vanity Fair

1. Most people advocating for Communism have never lived themselves in a communist country. The ‘grass-is-greener-on the other side’ lure is very strong.
2. Communism has an innate appeal in that it promises a heaven-on-Earth. Many people find this attractive. The fact that it cannot deliver this utopia in reality, is downplayed by the passion of its rhetoric. In short it has a romantic appeal that favors emotion over reason.
3. Communism’s central economic planning mantra reverberates with those who struggle with the short term uncertainty that the market economy delivers at times. What they fail to understand is that the market delivers feedback via the mechanism of price at a far more effective rate than the dated information that central planners are forced to rely on. It is for this reason that shortages are all too often a problem in centrally planned economies. Uncertainty is the price we pay for a more efficient system.
4. Communists speaks to a sense of entitlement through its propaganda, by focusing on what we ‘ought to have’ and ‘what is owed to us’.
5. Advocates of Communism consistently shift the goalposts when it is found wanting on the empirical front. We saw this after the Cold War. It denies previous failure by playing up the No True Scotsman fallacy.No True Scotsman
6. It promises vengeance against the other. This appeals to those who gain strength off their perceived Victimhood status. Ultimately this feeds into Nietzsche’s Will to Power.
7. Communism thrives when the populace is ignorant of history. The education system hasn’t helped in this regard which is why there is a chic to Communism in North America. Many people are barely aware of the horrors of Stalin’s Forced Famines/Purges, Mao’s Great Leap Forward, the Chinese Culture Revolution, Cambodia’s Killing Fields, Marxist destruction of the Ethiopian economy and numerous other examples. These evils need to be highlighted but are often downplayed. Each one of them is a function of Far Left social engineering. and failed economic collectivism.Mass killings under communist regimes - Wikipedia
8. Communism can mutate to broaden its appeal. We see this with race, gender and ethnicity replacing class as a key driver for change. Marxists have also been very successful in promoting their agenda in the church via the vehicle of Liberation Theology.They have also hijacked a great deal of the Environmental movement. Communism is hip again – but until it means liberty, count me out, comrade
9. The Gramscian March Through the Institutions has helped further the career of various Marxist apologists and Far Left ideologues in academia, the arts and the government. This has provided platforms of note from which these proponents can attack our Liberal Institutions with legitimacy of status. Why our intellectuals have missed the reality of Marxism and The Left's long march will be hard to stop
10. Communism has a cult like appeal. Some would say it is a secular religion. In terms of belonging to a system greater than oneself, communism hits this notion full on. This seems to be the appeal to millennials in a post-Christian Era.. What My Days as a Marxist Taught Me About Modern Political Cults - Quillette

Karl Marx - Cool dude according to some. Source: Liberty Maniacs.

Additional Reading

1. The Staggering Toll of the Russian Revolution | Yuri N. Maltsev
2. 100 Years of Communism—and 100 Million Dead
3. Why Antonio Gramsci is the Marxist thinker for our times