[trhway]

>the examples of cultures out-competing and replacing others through technology are rare

Alexander the Great - phalanx with resulting spread of Greek culture over all the Middle East, Roman Empire - countless advantages over the cultures they dominated, Vikings - sea faring ships and navigation, Columbus+/Americas and the whole colonial period across the world, ...

[aaaxyz]

I used the word culture but I really meant population in the sense that the original commenter used it (i.e. a group of people replacing or displacing another, rather than imposing their customs on another).

[sudosysgen]

Except for the last one, you're describing transmission not replacement.