> It gets really interesting once you express it in Delta V.

I mean, it does depend on how much time you're willing to spend. Yeah, the dV required to move from one asteroid to another is pretty tiny, but typical orbit phasing maneuvers like that typically take a long time to execute, especially in the scale of the asteroid belt (you gotta orbit all the way around the Sun).

That said, I feel like (but haven't validated mathematically or in e.g. KSP, or found real-life examples) it should be possible to do small phase shifts with radial burns (e.g. inward then outward to "catch up", or outward then inward to let the target do so) without requiring much of a time expenditure, though this would probably entail more fuel.