Socialism and Modernity
The fundamental limitations of the "why don't we have flying cars yet" argument: beyond the (admittedly reasonable) perspective that we wouldn't want the air to turn into the equivalent of a clogged-up arterial road, the argument is a fundamental misunderstanding of the nature of capitalist modernity, and of the "socialist" critique of capitalism.
Karl Marx viewed capitalism as "progressive" only in comparison to what came before it. Capitalism in his work was celebrated for unleashing the productive forces and enabling scientific and technological development, but only upto a point. Beyond that point, although not often explicitly stated in this exact form in his work, often restricted to the formulation that the forces of production come into conflict with the social relations of production, was a recognition that capitalism, after its progressive phase was over, was fundamentally a hindrance to the further growth of the productive forces, to the full flourishing of scientific and technological development.
Capitalist enterprises are fundamentally devoted to what Marx referred to as "capitalist accumulation". The inherent nature of their functioning dictates that they must derive more out of the production process than they put into it, that this "surplus value" or "capital" then must be reinvested in order to derive still more surplus value and so on and so forth. Often misunderstood as the "logic of profit", this is the basis of the capitalist system that remains regardless of "profit" or "loss".
Scientific and technological development, which form part of the growth of the productive forces, are subordinated to this logic as well. They must serve the purposes of capitalist accumulation, and are consequently directed narrowly in those specific directions that serve this purpose. The broader development of science and technology for the purpose of societal transformation is constrained, sometimes overtly limited and often fully halted, certainly never allowed to be unleashed in full.
Anarchic competition between capitalist enterprises further constrains the growth of scientific and technological development, restricting it to those "innovations" that help an enterprise accumulate more surplus value than its competitors. The state (or the government), referred to by Marx as "a committee for managing the affairs of the whole bourgeoisie", is committed to the preservation of this system.
In such a context, the futures of "Star Trek" and "Futurama", among other transformative futures envisioned by humankind, simply cannot emerge. The unleashing of the forces of scientific and technological development required for futures even more transformative than this, futures that Marx imagined could take place under a modernity freed from the limitations of capitalism, futures of a socialist society, are quite impossible.
The argument that "no true communist regime is repressive" is often presented as an example of a "no true Scotsman" fallacy. This profoundly reductive understanding of socialism is an unmitigated disaster. The "regime" envisioned in Vladimir Lenin's "State and Revolution", a libertarian "semi-state", was assumed to be for one purpose; to abolish class distinctions and carry out the transition to socialism, thereby rendering itself obsolete (in Marx's formulation, the state "withers away") and giving way to socialist society.
This "regime" never existed, except in Lenin's head and in the pages of "State and Revolution". After the Bolshevik seizure of power, Russia could add to its already considerable list of miseries (war, devastation and famine), an invasion by 14 foreign armies, a devastating economic blockade, a punishing peace treaty with Germany, and a civil war launched by White forces bent on the wholesale destruction of the nascent "workers' state".
Even this "workers' state" was rendered defunct before it could even begin the transition to socialism, by the need for rapid industrialization and the unpreparedness of the workers' state for administrating this vast country in the midst of such profound devastation. The Bolshevik party under Lenin suppressed what remained of it, "justified" by the need to suppress terrorist attacks launched on the Bolsheviks by their erstwhile allies and opponents in the Menshevik and Socialist-Revolutionary parties. What emerged afterwards was not only not socialism, it was not even a "dictatorship of the proletariat". The states that claimed the legacy of the Stalinist Soviet Union (or defined themselves in opposition to it but still claimed to be "socialist") are even less claimants to "socialism".
"Repression" was claimed as a temporary necessity in Marx and Engels' work due to the realisation that the capitalist state's functionaries and the capitalists would make every attempt to destroy a transitional "dictatorship of the proletariat" before it could carry out its world-historic task of abolishing class distinctions and carrying out the transition to socialism. Without classes, there would be no proletariat and no "dictatorship of the proletariat" (which would be rendered obsolete) and what would emerge would be socialist society.
This society would free scientific and technological development from the constraints of capitalism and create a modernity transformative beyond the most expansive visions of capitalist modernity. Socialist modernity would place technology in a conscious, regulated relationship with nature, healing what Marx called the "metabolic rift" between human society and nature, and enabling a world where technology becomes part of the processes contributing to the sustainability of the ecosystem, rather than a destructive outside influence. This would lay the foundations for rapid scientific and technological development for the creation of transformative futures while maintaining a self-sustaining natural ecosystem. These futures would be radically beyond "Star Trek", "Futurama" or any other futures imagined under capitalism.