Likely because it is a coded framework and not a handcrafted solution.
Bases itself on commander level as the key and then generates from there.

Problem is of course, taken to an extreme, that parts of content seem made for no reason as few can access it.

This would be less an issue if the event had a story and the story ended at, say, lvl40 with a boss fight and everything after that was post-event additional content "elite" maps with a mini PoC ladder and reward structure for fanatics.