First out, arto, if we are to extract a word from the whole of things for the purpose of functional communication we need to be clear about what exact attribute we need to abstract.

If you consider a culture to be static then you have to talk in relative terms, in that all cultures are in a continual state of transition from within by the natural interactions of the breeding group and the ever changing interactions with the environment or from without through the interactions and interventions of outside human groups.

As this is the case then your word must only have value in communicating sharp degrees of disintergration because the thing we call culture is arbitrary at best.

Can you more tightly define what it is you want?