the top of the pyramid is always the smallest
6v6, and specifically esea 6v6, has a higher skill level than any ugc league. marxist, the head ugc 6s admin, has accepted this and has (very successfully) tried to turn ugc 6s into a transitional league for newer teams, the "base" that feeds into open
there's nothing wrong with the most prestigious league having the fewest teams, that's like saying "lol invite only has 8 teams so invite tf2 is dead"