I'm not certain there are two factor mechanisms that can be readily implemented by individuals so I'm interpreting your comment as applying to organizations. Yes I've seen that people are resistant to change but that seems to be the human condition in general. We celebrate tradition.

The resistance I've experienced is two fold, resistance to change as you've identified, and resistance to spending money. Two factor authentication is an added cost no matter the computing infrastructure in place.

Overcoming resistance to change is the first hurdle. Allocating extra $ to implement and support 2 factor when there's "already passwords" is a management challenge. Depending who controls the $, who the users complain to about their job being harder and what part of the organization drives revenue IT (often) may not have the resources or authority to implement 2 factor.

In these cases IT must have strong partnerships with the other areas of the business if 2 factor will be implemented and succeed. I don't believe it's only the users.