Putting pieces back together

Leftists bemoan about the lack of will for unity among people, and them being and acting too seperated to be able to cause a change within the system.
But - what if that is a wish that is not possible anymore? What if the process of individualization that has taken place over decades has made them too different to be united unterneath a single claim?
Or, at least, if it has divided them in mentality and reality so much that it first requires work as long as the individualization process to overcome these trenches?