[Hmm... There's a lot to unpack here, so give him a moment.

The structure seems deliberately planned out to facilitate a sense of progression for trainers. Badges to show progress, with one final challenge at the very end...]

From the way you describe it, it almost seems... educational, for lack of a better word. If each gym represents a specific type, then when combined, they offer aspiring challengers opportunities to master the ins and outs of every type.