The opposite of narrativist gaming isn't gamist. It's causal gaming.

Causal: players describe what they attempt do, then GM determines how to resolve based on likely outcomes (possibly using dice), and describes resolution. Attempting actions causes likely outcomes.

Narrative: players describe what they attempt do, then GM determines how to resolve based on necessary narrative outcomes* (possibly using dice), and describes resolution. Attempting actions causes narratively necessary outcomes.

(Note in some narrative systems, players can directly determine the narrative and use mechanics to affect it. Ie I also agree with Mark above.)

*sometimes called "what would be most fun to happen here".