Comment by TZubiri

That property is true in most games though, unless it is heavily optimized for 'balance'. Consider Chess, or Poker, or Soccer, if both players play correctly a huge range of strategies are just easily exploitable and thus unplayed.

That said, complexity emerges and explodes in the tiny differences, even if there's like 8 pokemon that are in 95% of teams, and 10 situational pokemon that appear 5% of the times, that's like C(6,8) teams which is like 56 possible teams of Uber pokemon, and a buttload of possible teams with situational pokemon like choice scarf ditto, eviolite Chansey, nuzzle u-turn super fang pachirisu, etc...

Even if the teams were the same, just the possible differences in movesets create a lot of different sets, suppose 6 possible moves for each mon, you have C(4,6) sets for each mon, each with their own probability weight as well.