Rightwing dictatorships and fascists are good for US corporations and the US rich. So the capitalists of the world will always support fascism when it comes down to it. Every corporation in the US will support fascism if push comes to shove. For this reason, capitalism seems unsustainable because capitalists feel that the Left has no right to rule, and when it comes down to it, they will always support fascism, rightwing dictatorships, and fascist putschist oppositions to any existing leftwing governments.
It is for this reason that I feel that capitalism, which I do not necessarily oppose on moral grounds, is unsustainable and dangerous if not an out and out menace because of the tendency of all capitalist states when posed with a threat from the Left to install a fascist state. In other words, at some time or another in most capitalist countries, a threat will always cause a rightwing or fascist dictatorship to be installed.
Because of capitalism’s inevitable tendency towards rightwing dictatorship and fascism and its basic contempt for democracy, I feel that capitalism itself is a problem, and capitalism itself is a danger if not a menace to democratic society and people who wish to live free of dictatorships of the rich and fascism. In other words, yeah, capitalism in the long run is unsustainable.