Why don't south Americans travel much between borders?

I've known many Brazilians who travel from the south of Brazil all the way to the northern and northeastern states. That's about a 3,000 km trip. At least half of the Brazilians I've thoroughly talked to have told me so.

However, I rarely hear of Colombians traveling to Ecuador or Bolivians traveling to Argentina, even though the distance is similar. As far as I know, there is freedom of movement, and all you need is a driver's license to cross the borders, no visa needed, not even a passport is needed. I think even people who live near the borders don't go to the other country. even though it's just a two-hour drive. But they'll visit the other side of their own country, even if it's a 20-hour drive.

Maybe I'm just imagining things.