Yes that, and also, the more complicated the solution, the more likely no one reads or reviews it too carefully, and will instead depend on an LLM to ‘read’ and ‘review it’

Even ignoring token costs, there’s a high incentive for LLMs to generate complex solutions, because those solutions generate demand for further LLM use. (You don’t really want to review that 30,000 line pull request by hand, do you?)