Who talked about utopia? The USSR was far from a utopia, it was a state with flaws and lots of mistakes were made in the process. It is still demonstrably significantly more fair, egalitarian and less exploitative than anything we have in the west, which relies in the exploitation of the global south to sustain itself.

The whole "Utopian socialism" thing is a 200 years old argument that was dismantled back then, by the way. Engels himself has an essay called "Socialism: Utopian and Scientific", explaining how early branches of socialism followed utopian goals and methods, but Marxism is scientific socialism based off historical materialism and empiricism. If you look at my comments above, I've talked about historical evidence with hard data, not about good wishes for the future.

I don't see communism making any sustainable inroads anywhere in the world

That is if you ignore the main industrial powerhouse of the world (China), the island of Cuba, or the nations of Vietnam and Laos.

unless things get much much worse

As if, for example, the west started to support a genocide that murders over half a million people (most of them children), or if militarized police started kidnapping and disappearing random citizens without due process in the USA, or if fascist governments linked to Nazism and Fascism started to win elections in Italy or Germany?

Even then, it's just temporary until capitalism takes hold again

To quote Ursula K. Le Guin: "We live in capitalism. Its power seems inescapable. So did the divine right of kings"