What dud Karl marx and friedrich engels blame the horrible working conditions in factories?

Political philosopher Karl Marx and his partner, industrialist Friedrich Engels saw the capitalists and political leaders who advocated capitalism as the main source of poverty and exploitation in nations such as England and Germany. They wrote extensively about this and developed the idea of 'class struggle". Their view of history was that power within a nation changes via class struggle. They believed that human history can be predicted on a scientific basis. As capitalism developed, trade unions would become more powerful and overthrow their capitalist rulers. At some point in time, the Dictatorship of the proletariat would evolve into a classless society. Exploitation would end and nirvana would be created. This nirvana was communism.