It is not necessarily the case that this pineapple is shown to it's natural size, although the climate is very favorable in many parts of Ecuador. Exaggeration of physical size occurs so many places in the world.
However, one must wonder about the symbolism in that it is located in the middle of a traffic circle. Or you can ask the other way around(!), "why can't the dance just as well take place around a pineapple as a Christmas tree or a golden calf?"
-For this, we don't have any answers..