Wait, do you mean the top of the leaderboard is filled with actual persons and not with competitive programming teams trying to dominate the most visible event? If so, why?
What fantasy world is this? :D
Competitive programming teams, afaik, exist in the context of universities and they want to win ACM-ICPC, that's pretty much it. Otherwise, competitive programming is largely a solo affair.
In an event that yields no prize whatsoever, winning is just for bragging rights. There are no bragging rights in winning as a team against solo competitors.
Also, you only have one problem per night and AoC problems are too easy for it to make sense to have a team collaborating. The only thing a team would do is take the minimum solution time of their participants.