A lot of orchestral pieces have passages where a theme or phrase is passed from one group of instruments to another with slight variations: from flutes to clarinets to oboes to violins to bassons. A lot of those groups are between the middle and the left and half-way up the soundstage.
As I write there's a particularly soulful bit of Bruckner going on. It's all in the darker tones: middle C and lower: violas, cellos, oboe, clarinets. All in the middle and right.
If the composer has the orchestra playing a chord around middle C across the instrumental groups, the result will be a splotch across the soundstage. Because the instruments are literally positioned across the soundstage.
There are maybe two or three orchestras in the world, or maybe all of history, with string sections that change notes within a millisecond of each other, and all hit the exact same position on their (fretless) fingerboards. Seriously. Same with the wind players: it might be the same horn, but there will be tiny differences in the moment they start playing and in their breathing. The orchestral sound has smear built right into it. That's why it's such a relief when just one or two instruments play a soprano phrase: it sounds precise.
And this is before we even consider the difference between the way smaller ensembles are recorded - with one mic per instrument and other sound isolating methods - and the way orchestras are recorded with Decca trees and two other mics each side high up to add width.
If you are used to Nils Frahm, John Digweed or even Corelli and Bach, and then listen to even the best recording of Bruckner or Schumann, you're going to think something just went wrong with your hi-fi.
Nope. That's what orchestras sound like. All that gear that picks apart every bit of the sound and separates it from the others? Not going to work on the London Symphony Orchestra at full blast in Wagner. Many of the hi-fi reviewers are into rock, indie, jazz, electronica and perhaps some contemporary composed music: that stuff is well-treated by the kit they review. Heck, my mid-range system sounds fabulous when fed Nils Frahm, Chico Hamilton or John Jenkins. Not so sharp with even a modern recording of Dvorak or Bruckner, though much better now I have the speakers well-positioned, but I can't un-pick the clarinets from the oboes.