I think it's instructive to visualize the components in our systems as links in a chain. But, instead of the standard model of a chain, where each link is identical to the others, we need to instead form a chain of directional flow arrows where each link feeds its neighbor.
Source feeds control, which feeds power, then feeds speakers. Perhaps a better picture is to imagine a series of flow valves linked together. Music starts at one end of the chain and flows with as little restriction as possible.
Why does this seemingly obvious fact matter? Because we often judge individual links on their separate merits without considering how they mesh into the chain. A preamp that works wonders in one chain may not serve the needs of a different group of products.
We've talked of system synergy before, but perhaps it's helpful to approach the issue from the viewpoint of our chain/flow valve analogy instead.
The strongest flow results from every drop of music traveling together without the restriction of weak links.