Let's face it guys, the majority don't know or really care if there were real "heroes" wielding spears.
Think of the word "Medieval" and the thing that will most likely pop up first in your head is a plate-wearing knight wielding the biggest sword around, perhaps mounted on-top of a warhorse with the background of a castle or some combination of it.
All I'm saying is, popular culture with the sword burnt into most people's mind is a contributing factor for great sword popularity. At least it did for me, back in the days.
Massive swords are for the elite knights, spears are for the lowly peasants. Which weapon do you think most people would chose?