Maybe this is just a matter of definitions, but for me the point of an argument is to convince or be convinced. When two incompatible views exist on a subject, at least one of them must be wrong. Some topics of conversation allow for diverging views or values, but then we are just talking or sharing experiences, not arguing.
That said, it is my experience as well that actually changing someone's (or my own) mind on an important issue is unlikely. Especially on complex topics with partial and uncertain information, like political issues, our life experience and cumulative knowledge significantly influences our selection of sources and interpretation of the facts, so converging on a common point of view may require the exchange of a prohibitive amount of information, even among rational arguers.
Productive argument usually occurs in a sort of semi-echo chamber, with people who mostly agree with us on the context, and are only arguing about the top layer, so to say. But when trying to argue about the deep stuff, we are mostly just "exchanging views", in the end.