Why might people have difficulty accepting revolutionary ideas?
This is a good question. I would say that there many reasons why people would have a hard time accepting revolutionary ideas.
First, people are "programed" to accept the status quo. Sociologist call this ideology. To use the language of the great sociologist Peter Berger, people are institutionalized by those who have power to accept things as they way they are. They do not question the status quo as society shapes their thoughts.
Second, to think of revolutionary ideas is dangerous. A person must be willing to lose a lot. In fact, if the revolution is radical, he or she may also risk losing his or her life. Not many people are willing to do this.
Third, most people are comfortable where they are. So, why rock the boat? Truly revolutionary ideas, for the most part, come out of desparation and a desire for change. I will add a link to the social theories of Peter Berger.