Put inactive teams in same league, and active players against other active players

[July Fourth]

You really need to play this game for at least a year before you run into leagues with more active teams but even at Level 15 there can still be some inactive teams at this level.

[Accyrover]

Not totally relevant to being inactive but from say L5 upwards relegation would help to keep leagues stronger and fill all the voids left by accounts being deleted, which are the inactive teams in any case.
Bottom four go down, top six go up and four stay where they are.