I see both sides of this argument.
On one hand, those who have multiple teams in the same world DO get an advantage over the rest of us. They have knowledge of two teams, including FSS for both. They may even not be recruiting the same players on purpose, which is essentially colluding with yourself so you "both" get the recruits you want.
On the other hand, WIS probably doesn't want to cost itself a lot of money by alienating its best customers by making them remove some long-held teams.