Communism, like capitalism, is an extreme that has certain, very difficult to achieve, requirements. Capitalism needs everyone to be morally decent in order for companies to focus on winning customers through innovation instead of propganda and lobbying, and to accept losses instead of whining. Even the transition into communism is incredibly complicated and technically what where the USSR was stuck, and once there you have to hope that the rest of the world went along with it because it’ll work either on increbily small scales(individual companies, for example) or on a global scale but not really on a mid-sized scale. Plus in both you have basic greed and people who are literally just born narcissitic or legitimately psychotic.
Extreme ideologies are great thought experiments but rarely have any kind of well-developed protections built and are pretty fragile.
If you want a better answer, look at the quality of life in countries with stronger regulations and more communism-according-to-North America systems. In the heavily privatised U.S. there are a lot of people who live absolutely shit lives due to an abyssmal lack of protections. Even in Canada, which is far too close to the U.S. here, at least a homeless person can recieve some level of medical assistance including major surgeries and Covid stimulus was more than a cheap joke.