Do you believe that creating sub agents is a violation of the bitter lesson or is simply a way to add more context?
Sub agents are about providing targeted, specific information to the agents task, instead of having context around a billion other irrelevant topics.
The Database agent does not care at all about the instructions for your Agent Creator Agent. That is called negative context, or poison context, or whatever you want to call it.
So it's about targeted, specific, narrow instructions for a set of tasks.