System Synergy

I have always wondered this. I will go on a limb here and make the statement that many of us have different brands of amps/preamps/cd players/speakers/cabling within our system.

Remember the days when you went out and bought an all Sony/Pioneer/rack system?

We speak a lot about Synergy in high end. So why not have Gear from all the same brands, or at least a Preamp/Amp/CD player of the same brand? I would assume, internal parts, wires would be of the same brand. Isn't that a big part of Synergy?

Does anyone here have say an All Cary Audio System? Or all the same brand of IC and speaker wire? Im sure there are other brands which an entire system can be made of. Jadis, ...or at least a good portion of a system can be made.