A really big factor making up your ranking on the leaderboard is your ability to play in a chaotic game where your team and yourself aren't on the same page. Just taking the top players from the leaderboard (who aren't already on a top team) and putting them together makes up a team that is good enough to win against other similar random teams (hence their high rank) but can't win against actual teams, which is evidenced all the time in the open qualifers where actual teams that consist of lower ranked players beat them. TI open qualifer / regional qualifer / actual event placements are way better indicators on how good a team is than pub leaderboards.

The way TI is structured they invite one team from South America. So Pain is likely not in top 20, but still a very good team.