[Singollo]

Gotcha. So, you want to do away with cultural-specific "techs" altogether?

Changing the topic: why not have each star be sort of like a ringworld, with the equivalent of being like a larger city. That way you can have each star/city be the center of the surrounding area, with all other towns (planets) in the region (system) being outlying satellite towns or suburbs. That creates a more realistic idea of a piece of land, with one cultural center and a bunch of towns that spring up around it. (Obviously I don't mean that the culture starts with a free ringworld, just that the concept of a central uninhabitable star exerting gravity and keeping the planets near it should be translated as a central inhabitable town that exerts its cultural/political influence on the surrounding area.)