He also tried to predict the middle class' end in poverty, which, even during his lifetime, was stated to be wrong. And finally, he came up with the thought that there would be a proletarian revolution. This is where the middle class would try to overthrow the so called 'bourgeoisie', which from what I've read is the higher class society and exploiters of the working class. His inevitable revolution never seemed to come around.
Marx's theory works under the situation where the proletariat forces itself as ruler over the other classes (going against what our nation stands for). I'm sure he thought that the richer class would dictate because they were known to be more successful. But with the knowledge that the middle class was larger, it could have been the start of the revolution he was initially predicting. He was aware that a ruling needed to happen so that socialism would be in order.
And from socialism evolves communism. Similarities in both parties were the first recognition of dictatorship. Their motto's included the same will and act of what they stood for The socialists', "From each according to his ability, to each according to his work" to the communist slogan, "From each according to his ability, to each according to his needs." Their ideology was to unite the workers of the world (in the said image above). The word 'socialism' was in fact taken over by Leninist-Stalinist socialism, which is now known as communism. All these ideas originated in democratic countries who wanted to open trade and work economics with other countries. What would've happened if we had stayed on the trail of socialism?