Well, of course utopian states cannot exist. They wouldn't be utopian if they did. Perfection cannot exist in the natural world, hence we will never achieve 'pure' anything, be it communism, libertarianism, free markets or anarchy. Those utopian ideals are theoretical, rhetorical and designed to inspire. Similarly, these funny and frequently recurring threads about socialist states (which states are socialist, which aren't, which have failed, which were never socialist to begin with) all miss the point. In comparison with a right libertarian utopian ideal, all states are failed libertarian states, even, or especially the USA, because they all pursue elements of libertarian thinking allied with elements of statist, socialist, authoritarian and militarist policy and behaviour. In the same way, all states that have ever existed that called themselves, or were called socialist by others, failed because they too combined authoritarian, capitalistic, socialistic, militaristic, and democratic elements
The relevant point about, for example, the USSR is that it was an experiment in a different kind of political and social organisation that failed. As did Nazi Germany, and the Confederate States of America, and the French First Republic, and the English Commonwealth. All of those failed states combined many elements of various political ideologies and approaches, some socialistic, some nationalistic, some religiously-driven and some democratic. What failed in each and every one was the particular experiment, a combination of ideas, syndicates and individuals that was unique and about as far from 'pure' anything as anything can be. The ideas of socialism, libertarianism, nationalism, democracy or fascism do not cease to contain philosophical insight, whether you value that insight or not, solely because states or experiments where their tenets have been invoked or attempted, have failed.
There are elements of many ideologies that have been practiced to great success. There are elements of socialist ideology operating well in many, many countries, including the US, in forms that are far closer to 'pure' ideas deriving from Marxism than were ever tried in the USSR. The 'failure of socialism' as exemplified by the fall of the USSR and its satellites, was the failure of one interpretation of what socialism might mean. The reason I think socialism has far more to offer humanity than, say Nazism, is because elements of it are to be found influencing and inspiring successful regimes or elements of government all over the world, even in countries where the use of the word socialism has taken on bogeyman properties.
You might say the same about capitalism in countries like China and Vietnam, where it also possesses bogeyman status, yet who'd deny that elements of capitalism are alive and, relatively, well in so-called communist states? You can't say the same about Nazism, can you?