The word “socialism” is constantly being thrown about by supposed supporters and detractors alike, most of whom are people who have no clue as to what socialism actually is.
I am opposed to conventional socialism, which I actually consider to be a conservative philosophy (see Murray Rothbard’s essay “Left and Right” on this). Historically, socialist societies have been very conservative. There is no developed, “First World” country that practices socialism, and there never has been. The supposed “socialist” countries in Northern Europe practice a kind of “welfare capitalism” that is often more “free market” than the United States (where the market is subordinated to a kind of corporatist-financier-plutocratic-military-command economy, like an industrial-technological version of the economy of the Roman Empire).
Historically, socialism has appealed primarily to middle-class intellectuals and professionals in colonial societies and feudal countries whose national, political or class ambitions were being frustrated by either external colonialist/imperialist powers, or their own entrenched/inert ruling classes. Socialism was regarded as means of seizing the wealth of external colonial overlords, their colonial puppet rulers, and feudal elites, and utilizing this wealth for internal development (which is why Western colonial powers have been so opposed to socialism). Most of these countries eventually convert to capitalism (or simply stagnate or fall apart).
This Wikipedia entry listing socialist countries that have actually existed is pretty thorough. Notice that not a one of them is or has even been a Westernized industrial democracy. The “socialism” of Bernie Sanders, Alexandria Ocasia-Cortez, etc is standard welfare capitalism of the kind that developed in the late 19th and early 20th century through philosophies like progressivism, Fabianism, social democracy and reform liberalism.
Modern industrial economies are hybrids of market relations, and bureaucratic-managerial-administrative systems, with interlocking public, private, and independent sectors. Check out James Burnham’s work on the “managerial revolution” from the 1940s. He was an early observer of how classical bourgeois capitalism was being replaced with the modern, corporate, administrative kind. In a historical context socialism means either a nationalized economy that is directed by the state, or a worker run cooperative/syndicalist system, or some kind of New Harmony like utopian commune. However, the latter two examples are a fringe tendency within socialism (or have been during the past century), were denounced by Lenin as an “infantile disorder,” and are not what most people think of when they think of socialism.