This is, of course, only an analysis of Marx’s powers of prediction; and who was it said that prediction is difficult, especially about the future.
In defence of Marx I think we need to remember that Marx emphasised the importance of a well organised and class conscious proletariat. It would have the ability to control government through non governmental organisations, making the government the servant of the working class in much the same way as the capitalists control western democratic societies today. This is an important part of Marxist thought that you ignore.
The revolutions you quote did not happen this way. They have occurred in peasant / feudal or post colonial societies without a working class of any significance. Lenin tried to adapt Marxism to this situation with the concept of a working class vanguard; where the numerically small working class took control. This didn’t work, though it wasn’t helped by the civil war and US led invasion of the Soviet Union in the 1920s which killed off most of the committed revolutionaries.
Your article still leaves unanswered the interesting question of why socialist revolutions haven’t occurred in advanced industrial nations. My own thoughts are that we have to let capitalism run it’s course. Capitalism has been very flexible in extending it’s life by exploiting new markets to create new profits. But I think that in the long run the contradictions of capitalism that Marx detailed will catch up with it.
The 21st century could be that time. The erosion of the skilled worker base and middle management, the rise of the gig economy, the dominance of rentier capitalism are among many other developments that are squeezing the proletariat back into 19th century conditions. So far capitalism hasn’t got an answer to this; it is stagnating.