music with clear placement of the instruments.

Love Art Blakey. In that sample and in all jazz recordings of that era, a minimal amount of microphones were used, plus all members of the ensemble were playing together in one room. This technique provided a sense of space and "air" between the instruments. In the recording, the soundstage included the ambience of the room and an accurate reproduction of the location of each musician.

Not so today; multiple mic's are used and positioned close to each instrument...too close IMO. For example in the 50s and 60s the drums may have had only one or two mic's overhead, now-a-days each drum and cymbal gets it's own mic. This technique will make it more difficult to isolate one instrument. Of course there are engineers who know how get that open sound like the old jazz records.

Also, it's now common to record each musician alone in the studio and then combine the ensemble during the mixing process. The engineer can add reverb and other effects to simulate the entire group playing together, but the result will never have the same soundstage as the the early recordings.
Some of today's engineers can work magic and position the musicians in their proper space, but as you've noticed it can be hit or miss. It's the producer and the record label who decide the sonics of the album. You may already know about today's recording techniques, but I thought I would mention it anyway.

I just picked up a new Pat Metheny CD and the cymbals are positioned in front of Pat, and the drums sound like they're right next to him. And don't get me started on compression.

I'll add to Czariveys post. In a good concert hall and on a good recording you can certainly hear and visualize that the string section forms a semicircle in front and that the woodwinds are centered behind them. You can distantly hear each section but not any one instrument. (Unless it's a solo).
At home I can visualize the orchestra.