We used to record the Hong Kong Philharmonic during the era of Edo de Waart, using the Decca Tree technique with the 5 front microphones and 2 to 3 spot mics for the different sections depending on the pieces. This gives a good approximation of the Decca sound (even though we don't have the M50 mics) , and our halls are nowhere near the quality of Kingsway or Walthamstow halls. We ran two Nagra IV-S and a Tascam stereo DSD recorder off the Studer mixer, and multi-track PCM. The DSD and tape always sound better to my ears (my friend in charge of the PCM recording might not agree). Both RCA and Mercury used three microphones during the early period, with spectacular success. The secret is in positioning the orchestra within the hall to balance the sound. Most of the time, the seats for the audience are removed and the orchestra is placed in the middle of the hall, not on the stage.
A few years ago, we tried to get the contract for a recording project with the orchestra, but was beaten by a well known label. We went to one of the sessions anyway just to see what was going on. They had a mic in front of every player, without any partition. We didn't witness any attempt to optimise mic placement. They figured they would just capture the sound, and then correct any problem in post-production. But phase cancellations cannot be corrected. It is just not possible. The end result was, as expected, pretty disastrous. Somehow, the critics gave the CD rave reviews.