>>15705722You know, OP... consider this.
If Ash continued to use the same Pokemon, he would not have any other options or variance for matches that actually call for tough strategy. Each region, he continues to build up his army. But he has to start with fresh Pokemon, new recruits... otherwise, the potential for a new pokemon to reach elite ranks would be diminished.
Gym Matches are the new Pokemon's training.
League Matches is when he mobilizes his army.