I'm not questioning Cliffy on this, but from my experience (admittedly less geared toward classical music) synthesizers can place a huge demand on a system as well. Some gear just completely punts when it comes to trying to deal with synthesizers. Granted, that's not likely a very big consideration with most audiophiles, but if the artist is using synthesizers and the gear gives up, it's probably giving up with other demands as well.
As an example, Robert Palmer's, "You're in my System" uses a lot of them and if you've heard the song the way I suspect it was meant to sound and then heard it on a system that can't keep up with them then you get an idea of what I'm talking about. It's a tripping song done right or rather bleah when the playback is so-so.