Synergy

Impedance and gain compatibility are engineering reasons for the basis of synergy, however, for most audiophiles I'm of the opinion that synergy is an explanation for personal sonic preferences. Why use tone controls when you can mix and match components. Using a single brand of components would take away much of the fun of this hobby.

Only slightly more seriously, only a small number of companies are equally proficient at making source components, amplifiers and loudspeakers. McIntosh, Meridien, Sony, Krell, Harmon Group, Linn and Yamaha are some of the exceptions to the rule.

The soup analogy is very misleading. Cooking is more akin to making music as an activity in that it has an element of creativity. The reproduction of music is of an order of magnitude less complex than those activities as it lacks the creative part. Putting together a system seems to be a very mechanical process. You gather information about what you think will work well and then you try it. If you like the results you say it works synergistically. If you don't like the sound you fiddle until you do like it or you move on to the next "upgrade". Trail and error ain't creative. It's a rote process.

Furthermore, the soup analogy is misleading because it gives too much freedom of expression to the audiophile. Unless a cook is working in a commercial environment, there is no compelling reason for tonight's soup to taste just like yesterday's version. Cooks are expected to experiment and modify. Audiophiles don't have that leeway because we are trying to reproduce something that is a known quantity. (We may not know exactly what the recording is supposed to sound like, but there is an artist/producer/engineer somewhere that does.) This limits what the audiophile can do and still call the result high fidelity sound.