This is such a pessimistic view of things. As the hero pool expands, the training challenge increases at the rate of n^10. So going from 16 to 25 - we have ~100x blowup in hero combinations, likely requiring significantly more compute to train.
OpenAI Five is the first AI to beat the world champions in an esports game, having won two back-to-back games versus the world champion Dota 2 team, OG, at Finals this weekend.
What they've achieved is actually impressive, too, so the deception is doubly annoying.