You make some interesting points, as usual. On this bit …
“Utopian” – many mean it as pie in the sky, can never happen in reality. Never is a long time! Homo sapiens first appeared as a distinct species 300,000 years ago and until about 10,000 years ago lived in small, nomadic groups with low population density who typically valued cooperation, sharing, egalitarianism, and social cohesion (or so current thinking says).
10,000 years ago the first agricultural revolution led to a significant shift in human societies - larger, settled agricultural communities. More hierarchical social structures began to evolve. Big business began … what, within the last couple hundred years…? less?
So human social evolution – only in the last 3% of our existence as a species – has undergone radical changes. And the rate of change seems to be accelerating ever faster, certainly since the Industrial Revolution.
Therefore it’s quite possible what looks ‘utopian’ can change very quickly, like nearly everything else.
Second point - you suggest ‘socialism’ can never last long due to "human greed and vulnerability to external disturbances." Not sure precisely what you mean by this. But from what (little) I know of the Russian revolution – which was the first conscious attempt to overthrow capitalism within a country – no sooner had it occurred than the forces of capitalism rallied to attack and bring it down. Not only the ousted capitalist class, but the other capitalist countries – UK, France Japan, the US and others sent troops and supplies to support the various ‘White Army’ forces. Those other countries also cut off trade and imposed embargoes on Russia.
In every other case where capitalism has come under threat from a communist uprising the same thing has happened. For obvious reasons capitalists of the world view communism anywhere as a potential existential threat to their interests and do whatever they can to crush it.
I realise some think they have won this battle! But stepping back to look at history from a wider perspective – hasn’t all this only just begun to play out? We are at a stage of human social and economic development that has never existed before, and the contradictions of capitalism have certainly not been resolved.
As for Donald, his ascension while spectacular is not unique. Capitalism is creaking and groaning in many places around the world, and the US is not the only place where the extreme right is currently gaining in influence.