Vietnam is socialist and even the capitalist global institutions are astounded at their recent economic progress. Cuba beats us in a number of ways, in healthcare, literacy, life expectancy, etc. Cuba has been described as the most "sustainably developed country in the world". Still, I prefer the decentralized communism like the Zapatistas practice in Chiapas to democratic centralism.
A system that permits people to starve and go homeless amidst abundance is an abject failure. Capitalism allows everyone to struggle except the richest 1%. Read a book, seriously, because it wasn't like this before capitalism. Many examples of people being forced into capitalist production, in some cases because the subsistence lifestyle was preferable than offered wages.